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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2011	Feb. 22, 2012	Jun. 30, 2011
Document and Entity Information [Abstract]
Entity Registrant Name	CoreSite Realty Corp
Entity Central Index Key	0001490892
Document Type	10-K
Document Period End Date	Dec. 31, 2011
Amendment Flag	false
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 215.9
Entity Common Stock, Shares Outstanding		20,748,396

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010
Investments in real estate:
Land	$ 84,738	$ 84,738
Building and building improvements	499,717	450,097
Leasehold improvements	81,057	75,800
Total investments in real estate	665,512	610,635
Less: Accumulated depreciation and amortization	(64,428)	(32,943)
Net investment in operating properties	601,084	577,692
Construction in progress	73,084	11,987
Net investments in real estate	674,168	589,679
Cash and cash equivalents	6,628	86,246
Restricted cash	9,291	14,968
Accounts and other receivables, net of allowance for doubtful accounts of $465 and $305 as of December 31, 2011 and 2010, respectively	6,562	5,332
Lease intangibles, net of accumulated amortization of $33,711 and $17,105 as of December 31, 2011 and 2010, respectively	36,643	71,704
Goodwill	41,191	41,191
Other assets	33,743	23,906
Total assets	808,226	833,026
Liabilities:
Revolving credit facility	5,000	0
Mortgage loans payable	116,864	124,873
Accounts payable and accrued expenses	38,822	26,393
Deferred rent payable	3,535	2,277
Acquired below-market lease contracts, net of accumulated amortization of $9,267 and $4,989 as of December 31, 2011 and 2010, respectively	11,872	16,415
Prepaid rent and other liabilities	11,946	8,603
Total liabilities	188,039	178,561
Stockholders' equity:
Common stock, par value $0.01, 100,000,000 shares authorized and 20,747,794 and 19,644,042 shares issued and outstanding at December 31, 2011 and 2010, respectively	204	194
Additional paid-in capital	256,183	239,453
Accumulated other comprehensive income (loss)	(34)	52
Accumulated deficit	(23,545)	(7,460)
Total stockholders' equity	232,808	232,239
Noncontrolling interests	387,379	422,226
Total equity	620,187	654,465
Total liabilities and equity	$ 808,226	$ 833,026

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Allowance for doubtful accounts	$ 465	$ 305
Accumulated amortization, lease intangibles	33,711	17,105
Accumulated amortization, acquired below-market lease contracts	$ 9,267	$ 4,989
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	20,747,794	19,644,042
Common stock, shares outstanding	20,747,794	19,644,042

Consolidated Statement of Operations - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2010	Sep. 27, 2010	Dec. 31, 2011	Dec. 31, 2009
Operating expenses:
Net loss			$ (10,779)	$ (7,039)
The Company
Operating revenues:
Rental revenue	$ 24,428		108,597
Power revenue	9,403		43,402
Tenant reimbursement	1,501		6,344
Other revenue	3,020		14,503
Total operating revenues	38,352		172,846
Operating expenses:
Property operating and maintenance	12,107		55,049
Real estate taxes and insurance	1,642		9,119
Depreciation and amortization	19,146		68,967
Sales and marketing	1,341		5,744
General and administrative	4,987		21,846
Transaction costs	3,275		875
Rent	4,551		18,336
Total operating expenses	47,049		179,936
Operating income (loss)	(8,697)		(7,090)
Gain on early extinguishment of debt			939
Interest income	77		117
Interest expense	(2,325)		(5,275)
Loss before income taxes	(10,945)		(11,309)
Income tax benefits	223		530
Net loss	(10,722)		(10,779)
Net loss attributable to noncontrolling interests	(7,371)		(6,168)
Net loss attributable to common shares	$ (3,351)		$ (4,611)
Basic and diluted loss per common share
Net loss per share attributable to common shares	$ (0.17)		$ (0.24)
Weighted average common shares outstanding	19,458,605		19,609,375
The Predecessor
Operating revenues:
Rental revenue		$ 24,377		18,974
Power revenue		8,520		7,372
Tenant reimbursement		1,406		1,061
Other revenue		1,254		1,424
Total operating revenues		35,557		28,831
Operating expenses:
Property operating and maintenance		14,272		13,954
Real estate taxes and insurance		1,262		1,787
Management fees to related party		3,582		2,244
Depreciation and amortization		11,848		11,193
Sales and marketing		125		135
General and administrative		2,258		1,401
Rent		2,177		2,816
Total operating expenses		35,524		33,530
Operating income (loss)		33		(4,699)
Interest income		2		3
Interest expense		(1,590)		(2,343)
Loss before income taxes		(1,555)		(7,039)
Net loss		(1,555)		(7,039)
Net loss attributable to common shares		$ (1,555)		$ (7,039)

Consolidated Statement of Stockholders' Equity And Comprehensive Income - USD ($) $ in Thousands	Total	Common Shares Number	Redeemable Noncontrolling Interests	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Member's Equity	Total Stockholders' Equity	Noncontrolling Interests
Beginning balance at Dec. 31, 2008	$ 149,103	$ 0	$ 0	$ 0	$ 0	$ 0	$ 149,103	$ 149,103	$ 0
Beginning balance, shares at Dec. 31, 2008		0
Contributions	20,274						20,274	20,274
Comprehensive income:
Net loss	(7,039)						(7,039)	(7,039)
Ending balance at Dec. 31, 2009	162,338	$ 0	0	0	0	0	162,338	162,338	0
Ending balance, shares at Dec. 31, 2009		0
Contributions	33,399						33,399	33,399
Distributions	(2,000)						(2,000)	(2,000)
Initial capitalization of CoreSite Realty Corporation, shares		1,000
Issuance of common stock, shares		19,435,000
Issuance of common stock	310,960	$ 194		310,766				310,960
Issuance of Operating Partnership units in exchange for 100% of the interests in our predecessor	(236,764)		236,764				(236,764)	(236,764)
Issuance of Operating Partnership units in exchange for 100% of the interests in the CoreSite Acquired Properties			316,836
Redemption of Operating Partnership units for cash			(125,513)
Offering costs	(25,306)			(25,306)				(25,306)
Reclassify members equity to additional paid in capital				(43,027)			43,027
Issuance of stock awards, shares		208,042
Issuance of stock awards	361			361				361
Issuance of equity incentive Operating Partnership units			975
Amortization of deferred compensation	538			538				538
Dividends and distributions	(5,967)				(2,554)			(2,554)	(3,413)
Adjustment to reflect redeemable noncontrolling interest at redemption value	(3,879)		3,879	(3,879)				(3,879)
Comprehensive income:
Net loss	(9,181)		(3,096)		(4,906)			(4,906)	(4,275)
Unrealized gain on derivative contracts	121					52		52	69
Comprehensive loss	(9,060)		(3,096)					(4,854)	(4,206)
Reclassify redeemable noncontrolling interests to permanent equity	429,845		(429,845)						429,845
Ending balance at Dec. 31, 2010	654,465	$ 194	0	239,453	(7,460)	52	0	232,239	422,226
Ending balance, shares at Dec. 31, 2010		19,644,042
Offering costs	(17)			(17)				(17)
Amortization of deferred compensation	2,958	$ 1		2,957				2,958
Dividends and distributions	(26,278)				(11,474)			(11,474)	(14,804)
Comprehensive income:
Net loss	(10,779)				(4,611)			(4,611)	(6,168)
Unrealized gain on derivative contracts	(366)					(163)		(163)	(203)
Reclassification of other comprehensive loss to interest expense	173					77		77	96
Comprehensive loss	(10,972)							(4,697)	(6,275)
Redemption of noncontrolling interests, shares		889,610
Redemption of noncontrolling interests		$ 9		13,759				13,768	(13,768)
Issuance of restricted stock awards, net of forfeitures, shares		212,180
Exercise of stock options, shares		1,962
Exercise of stock options	31			31				31
Ending balance at Dec. 31, 2011	$ 620,187	$ 204	$ 0	$ 256,183	$ (23,545)	$ (34)	$ 0	$ 232,808	$ 387,379
Ending balance, shares at Dec. 31, 2011		20,747,794

Consolidated Statement of Stockholders' Equity And Comprehensive Income (Parenthetical)	12 Months Ended
	Dec. 31, 2010
The Predecessor
Percentage interests in predecessor in exchange for issuance of operating partnership units	100.00%
Redeemable Noncontrolling Interests
Percentage interests in CoreSite Acquired Properties in exchange for issuance of operating partnership units	100.00%
Acquired Properties
Percentage interests in predecessor in exchange for issuance of operating partnership units	100.00%

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2010	Sep. 27, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss			$ (10,779)	$ (9,181)	$ (7,039)
CASH FLOWS FROM FINANCING ACTIVITIES
Cash and cash equivalents, beginning of period			86,246
Cash and cash equivalents, end of period	$ 86,246		6,628	86,246
The Company
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	(10,722)		(10,779)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	19,146		68,967
Amortization of above/below market leases	(390)		(1,650)
Amortization of deferred financing costs	427		1,556
Gain on early extinguishment of debt			(939)
Amortization of share-based compensation	538		2,958
Amortization of discount to fair market value of acquired loan	916		687
Bad debt expense	25		292
Changes in operating assets and liabilities:
Restricted cash	3,670		712
Accounts receivable	(1,790)		(1,523)
Due to and due from related parties			2
Deferred rent receivable	(995)		(4,986)
Deferred leasing costs	(503)		(4,215)
Other assets	(987)		(1,227)
Accounts payable and accrued expenses	(176)		7,273
Prepaid rent and other liabilities	1,528		2,820
Deferred rent payable	400		1,258
Net cash provided by operating activities	11,087		61,206
CASH FLOWS FROM INVESTING ACTIVITIES
Real estate improvements	(11,348)		(117,524)
Assumption of cash balances in connection with the contribution of the CoreSite Acquired Properties	10,269
Changes in reserves for capital improvements	50		4,965
Net cash used in investing activities	(1,029)		(112,559)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of common stock	310,960
Offering costs	(25,182)		(17)
Proceeds from exercise of stock options			31
Redemption of operating partnership units	(125,513)
Proceeds from revolving credit facility			5,000
Proceeds from mortgage loans payable	60,000		6,440
Repayments of mortgage loans payable	(152,600)		(14,189)
Payments of loan fees and costs	(3,440)		(1,745)
Reduction in contribution receivables	2,703
Dividends and distributions			(23,785)
Net cash provided by (used in) financing activities	66,928		(28,265)
Net change in cash and cash equivalents	76,986		(79,618)
Cash and cash equivalents, beginning of period	9,260		86,246
Cash and cash equivalents, end of period	86,246	$ 9,260	6,628	86,246
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest	1,278		4,360
NON-CASH INVESTING AND FINANCING ACTIVITY
Construction costs payable capitalized to real estate	2,890		5,564
Contribution of the CoreSite Acquired Properties for Operating Partnership units	316,836
Accrual of dividends and distributions	5,967		$ 8,453	5,967
Accrued offering costs	124
The Predecessor
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss		(1,555)			(7,039)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization		11,848			10,368
Amortization of above/below market leases		(171)			(206)
Amortization of deferred financing costs		323			490
Bad debt expense		(82)			310
Changes in operating assets and liabilities:
Restricted cash		(250)			(323)
Accounts receivable		583			470
Due to and due from related parties		875			(783)
Deferred rent receivable		(1,656)			(2,312)
Deferred leasing costs		(4,449)			(2,182)
Other assets		(253)			60
Accounts payable and accrued expenses		(317)			1,065
Prepaid rent and other liabilities		(222)			1,279
Deferred rent payable		143			239
Net cash provided by operating activities		4,817			1,436
CASH FLOWS FROM INVESTING ACTIVITIES
Real estate improvements		(44,691)			(28,043)
Changes in reserves for capital improvements		239			591
Net cash used in investing activities		(44,452)			(27,452)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from mortgage loans payable		10,302			9,857
Payments of loan fees and costs		(272)			(144)
Contributions		33,399			20,274
Dividends and distributions		(2,000)
Net cash provided by (used in) financing activities		41,429			29,987
Net change in cash and cash equivalents		1,794			3,971
Cash and cash equivalents, beginning of period	$ 9,260	7,466		$ 7,466	3,495
Cash and cash equivalents, end of period		9,260			7,466
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest		1,193			1,919
NON-CASH INVESTING AND FINANCING ACTIVITY
Construction costs payable capitalized to real estate		$ 1,516			$ 1,721

Organization

12 Months Ended

Dec. 31, 2011

Organization [Abstract]

Organization

1. Organization

CoreSite Realty Corporation (the “Company,” “we,” or “our”) was organized in the state of Maryland on February 17, 2010 and is a fully integrated, self-administered, and self-managed real estate investment trust (“REIT”). Through our controlling interest in CoreSite, L.P. (our “Operating Partnership”), we are engaged in the business of owning, acquiring, constructing and managing technology-related real estate.

On September 28, 2010, we completed our initial public offering (the “IPO”) which resulted in the sale of 19,435,000 shares of our common stock at a price per share of $16.00, generating net proceeds to the Company of $285.6 million.

Upon completion of the IPO, our Operating Partnership entered into various formation transactions and acquired 100% of the ownership interests in the entities that owned our Predecessor, as defined below, from certain real estate funds (the “Funds”) affiliated with The Carlyle Group. Our Predecessor includes the limited liability companies which were all wholly owned, directly or indirectly, by CRP Fund V Holdings, LLC. We determined that CRP Fund V Holdings, LLC was the acquirer for accounting purposes and, therefore, interests contributed by CRP Fund V Holdings, LLC in the formation transactions (the Predecessor entities and properties) were recorded at historical cost.

Additionally, our Operating Partnership acquired 100% of the ownership interests in the entities that owned the CoreSite Acquired Properties, as defined below, from the Funds and their affiliates. The contribution or acquisition of interests in the CoreSite Acquired Properties was accounted for as an acquisition under the acquisition method of accounting and recognized at the estimated fair value of acquired assets and assumed liabilities on the date of the contribution.

The financial condition and results of operations for the entities acquired by our Predecessor in connection with the IPO and related formation transactions are only included in the consolidated financial statements since the date of the transactions. Prior to the date of the transactions of September 28, 2010, the consolidated financial statements include only the activities and capital structure of our Predecessor. More specifically, our results of operations for the year ended December 31, 2010 reflect the operations of the consolidated Predecessor entities as defined in the table below, together with the CoreSite Acquired Properties from the date of their acquisition. Changes in our capital structure that occurred on September 28, 2010, including the acquisition of our Predecessor by our Operating Partnership, are reflected since that date in the financial statements including the allocation of net loss attributable to noncontrolling interest holders and calculations of loss per share. The accompanying consolidated financial statements include the following entities and properties:


CoreSite Predecessor		Coresite Acquired Properties
CRP Fund V Holdings, LLC		One Wilshire
1656 McCarthy		900 N. Alameda
2901 Coronado		55 S. Market
Coronado-Stender Properties		427 S. LaSalle
70 Innerbelt		1275 K Street
32 Avenue of the Americas		2115 NW 22nd Street
12100 Sunrise Valley		CoreSite, LLC

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2011

Summary of Significant Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Principles of Consolidation and Basis of Presentation

The accompanying consolidated financial statements have been prepared by management in accordance with U.S. generally accepted accounting principles (“GAAP”). Intercompany balances and transactions have been eliminated in these consolidated financial statements. The Company reviewed subsequent events through the issuance date for inclusion in these consolidated financial statements.

Use of Estimates

The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingencies at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. We evaluate our estimates, including those related to assessing the carrying values of our real estate properties, accrued liabilities, performance-based equity compensation plans, and qualification as a REIT. We base our estimates on historical experience, current market conditions, and various other assumptions that we believe to be reasonable under the circumstances. Actual results may vary from those estimates and those estimates could vary under different assumptions or conditions.

Investments in Real Estate

Real estate investments are carried at cost less accumulated depreciation and amortization. The cost of real estate includes the purchase price of the property and leasehold improvements. Expenditures for maintenance and repairs are expensed as incurred. Significant renovations and betterments that extend the economic useful lives of assets are capitalized. During the development of the properties, the capitalization of costs, which include interest, real estate taxes and other direct and indirect costs, begins upon commencement of development efforts and ceases when the property is ready for its intended use. Interest is capitalized during the period of development based upon applying the weighted-average borrowing rate to the actual development costs expended. Capitalized interest costs were $1.6 million, less than $0.1 million and $0.5 million for the year ended December 31, 2011, for the period from September 28, 2010 to December 31, 2010 and for the period from January 1, 2010 to September 27, 2010, respectively, and were not significant for the year ended December 31, 2009.

Depreciation and amortization are calculated using the straight-line method over the following useful lives of the assets:


Buildings		27 to 40 years
Building improvements		1 to 15 years
Leasehold improvements		The shorter of the lease term or useful life of the asset

Depreciation expense was $33.7 million, $7.4 million, $9.6 million and $9.2 million for the year ended December 31, 2011, for the period from September 28, 2010 to December 31, 2010, for the period from January 1, 2010 to September 27, 2010 and the year ended December 31, 2009, respectively.

Acquisition of Investment in Real Estate

Purchase accounting is applied to the assets and liabilities related to all real estate investments acquired. The fair value of the real estate acquired is allocated to the acquired tangible assets, consisting primarily of land, building and improvements, and identified intangible assets and liabilities, consisting of the value of above-market and below-market leases, value of in-place leases and the value of customer relationships.

The fair value of the land and building of an acquired property is determined by valuing the property as if it were vacant, and the “as-if-vacant” value is then allocated to land and building based on management’s determination of the fair values of these assets. Management determines the as-if-vacant fair value of a property using methods similar to those used by independent appraisers. Factors considered by management in performing these analyses include an estimate of carrying costs during the expected lease-up periods considering current market conditions and costs to execute similar leases.

The fair value of intangibles related to in-place leases includes the value of lease intangibles for above-market and below-market leases, lease origination costs, and customer relationships, determined on a lease-by-lease basis. Above-market and below-market leases are valued based on the present value (using an interest rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to the in-place leases and (ii) management’s estimate of fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease and, for below-market leases, over a period equal to the initial term plus any below-market fixed rate renewal periods. Lease origination costs include estimates of costs avoided associated with leasing the property, including tenant allowances and improvements and leasing commissions. Customer relationship intangibles relate to the additional revenue opportunities expected to be generated through interconnection services and utility services to be provided to the in-place lease tenants.

The capitalized values for above and below-market lease intangibles, lease origination costs, and customer relationships are amortized over the term of the underlying leases. Amortization related to above-market and below-market leases where the Company is the lessor is recorded as either an increase to or a reduction of rental income, amortization related to above-market and below-market leases where the Company is the lessee is recorded as either an increase to or a reduction of rent expense and amortization for lease origination costs and customer relationships are recorded as amortization expense. If a lease is terminated prior to its stated expiration, all unamortized amounts relating to that lease are written off. The carrying value of intangible assets is reviewed for impairment in connection with its respective asset group whenever events or changes in circumstances indicate that the asset group may not be recoverable. An impairment loss is recognized if the carrying amount of the asset group is not recoverable and its carrying amount exceeds its estimated fair value.

The excess of the cost of an acquired business over the net of the amounts assigned to assets acquired (including identified intangible assets) and liabilities assumed is recorded as goodwill. As of December 31, 2011 and 2010, we had approximately $41.2 million of goodwill. The Company’s goodwill has an indeterminate life and is not amortized, but is evaluated for impairment on an annual basis, or more frequently if events or changes in circumstances indicate that the asset might be impaired. None of the Company’s current goodwill is deductible for tax purposes.

Cash and Cash Equivalents

Cash and cash equivalents include all non-restricted cash held in financial institutions and other non-restricted highly liquid short-term investments with original maturities at acquisition of three months or less.

Restricted Cash

We are required to maintain certain minimum cash balances in escrow by loan agreements to cover various building improvements and obligations related to tax assessments and insurance premiums. We are legally restricted by these agreements from using this cash other than for the purposes specified therein.

Deferred Costs

Deferred leasing costs include commissions and other direct and incremental costs incurred to obtain new customer leases, which are capitalized and amortized over the terms of the related leases using the straight-line method. If a lease terminates prior to the expiration of its initial term, any unamortized costs related to the lease are written off to amortization expense.

Deferred financing costs include costs incurred in connection with obtaining debt and extending existing debt. These financing costs are capitalized and amortized on a straight-line basis, which approximates the effective-interest method, over the term of the loan and are included as a component of interest expense.

Impairment of Long-Lived Assets

We review long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Impairment is recognized when estimated expected future cash flows (undiscounted and without interest charges) are less than the carrying amount of the assets. The estimation of expected future net cash flows is inherently uncertain and relies to a considerable extent on assumptions regarding current and future economics and market conditions and the availability of capital. If, in future periods, there are changes in the estimates or assumptions incorporated into the impairment review analysis, the changes could result in an adjustment to the carrying amount of the assets. To the extent that an impairment has occurred, the excess of the carrying amount of long-lived assets over its estimated fair value would be charged to income. For the years ended December 31, 2011, 2010 and 2009, no impairment was recognized.

Derivative Instruments and Hedging Activities

We reflect all derivative instruments at fair value as either assets or liabilities on the consolidated balance sheets. For those derivative instruments that are designated, and qualify, as hedging instruments, we record the effective portion of the gain or loss on the hedge instruments as a component of accumulated other comprehensive income. Any ineffective portion of a derivative’s change in fair value is immediately recognized in earnings. For derivatives that do not meet the criteria for hedge accounting, changes in fair value are immediately recognized in earnings.

Revenue Recognition

All leases are classified as operating leases and minimum rents are recognized on a straight-line basis over the non-cancellable term of the agreements. The excess of rents recognized over amounts contractually due pursuant to the underlying leases are included in deferred rent receivable. If a lease terminates prior to its stated expiration, the deferred rent receivable relating to that lease is written off as a reduction of rental revenue.

When arrangements include both lease and nonlease elements, the revenue associated with separate elements are allocated based on their relative fair values. The revenue associated with each element is then recognized as earned. Interconnection, utility and power services are considered as separate earnings processes that are provided and completed on a month-to-month basis and revenue is recognized in the period that the services are performed. Utility and power services are included in power revenue in the accompanying statements of operations. Interconnection services are included in other revenue in the accompanying statements of operations. Set-up charges and utility installation fees are initially deferred and recognized over the term of the arrangement as other revenue or the expected period of performance unless management determines a separate earnings process exists related to an installation charge.

Tenant reimbursements for real estate taxes, common area maintenance, and other recoverable costs are recognized in the period that the expenses are incurred.

A provision for uncollectible accounts is recorded if a receivable balance relating to contractual rent, rent recorded on a straight-line basis, or tenant reimbursements is considered by management to be uncollectible. At December 31, 2011 and 2010, the allowance for doubtful accounts totaled $0.5 million, and $0.3 million, respectively. Additions to the allowance for doubtful accounts were $0.3 million, less than $0.1 million, $0.2 million, and $0.3 million, for the year ended December 31, 2011, for the period from September 28, 2010 to December 31, 2010, for the period from January 1, 2010 to September 27, 2010 and the year ended December 31, 2009, respectively. Write-offs (recoveries) charged against the allowance were $0.1 million, $0.1 million, $0.1 million, and $0.4 million, for the year ended December 31, 2011, for the period from September 28, 2010 to December 31, 2010, for the period from January 1, 2010 to September 27, 2010 and the year ended December 31, 2009, respectively.

Share-Based Compensation

We account for share-based compensation using the fair value method of accounting. The estimated fair value of the stock options granted by us is being amortized on a straight-line basis over the vesting period of the stock options. The fair value of restricted share-based and Operating Partnership unit compensation is based on the market value of our common stock on the date of the grant and is amortized on a straight-line basis over the vesting period.

Asset Retirement Obligations

We record accruals for estimated retirement obligations. The asset retirement obligations relate primarily to the removal of asbestos and contaminated soil during development or redevelopment of the properties as well as the estimated equipment removal costs upon termination of a certain lease where the Company is the lessee. At December 31, 2011 and 2010, the amount included in other liabilities on the consolidated balance sheets was approximately $1.9 million and $2.1 million, respectively.

Income Taxes

We have elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”), commencing with our initial taxable year ending December 31, 2010. To qualify as a REIT, we are required to distribute at least 90% of our taxable income to our stockholders and meet the various other requirements imposed by the Code relating to such matters as operating results, asset holdings, distribution levels and diversity of stock ownership. Provided we qualify for taxation as a REIT, we are generally not subject to corporate level federal income tax on the earnings distributed currently to our stockholders. If we fail to qualify as a REIT in any taxable year, and are unable to avail ourselves of certain savings provisions set forth in the Code, all of our taxable income would be subject to federal income tax at regular corporate rates, including any applicable alternative minimum tax.

To maintain REIT status we will distribute a minimum of 90% of the Company’s taxable income. However, it is our policy and intent, subject to change, to distribute 100% of the Company’s taxable income and therefore, no provision is required in the accompanying financial statements for federal income taxes with regards to activities of the REIT and its subsidiary pass-through entities. Any taxable income prior to the completion of the IPO is the responsibility of the Company’s prior members. The allocable share of income is included in the income tax returns of the members. The Company is subject to the statutory requirements of the locations in which it conducts business. State and local income taxes are accrued as deemed required in the best judgment of management based on analysis and interpretation of respective tax laws.

We have elected to treat one of our subsidiaries as a taxable REIT subsidiary (“TRS”). Certain activities that we undertake must be conducted by a TRS, such as services for our tenants that would otherwise be impermissible for us to perform and holding assets that we cannot hold directly. A TRS is subject to corporate level federal and state income taxes. Relative deferred tax assets and liabilities arising from temporary differences in financial reporting versus tax reporting are also established as determined by management.

Deferred income taxes are recognized in certain taxable entities. Deferred income tax is generally a function of the period’s temporary differences (items that are treated differently for tax purposes than for financial reporting purposes), the utilization of tax net operating losses generated in prior years that had been previously recognized as deferred income tax assets and the reversal of any previously recorded deferred income tax liabilities. A valuation allowance for deferred income tax assets is provided if we believe all or some portion of the deferred income tax asset may not be realized. Any increase or decrease in the valuation allowance resulting from a change in circumstances that causes a change in the estimated realizability of the related deferred income tax asset is included in deferred tax expense. As of December 31, 2011 and 2010, the deferred income taxes were not material.

We currently have no liabilities for uncertain tax positions. The earliest tax year that we are subject to examination is 2010. Prior to their contribution to our Operating Partnership, our subsidiaries were treated as pass-through entities for tax purposes and the earliest year subject to examination of our subsidiaries is 2008.

Concentration of Credit Risks

Our cash and cash equivalents are maintained in various financial institutions, which, at times, may exceed federally-insured limits. We have not experienced any losses in such accounts, and management believes that we are not exposed to any significant credit risk in this area. We have no off-balance-sheet concentrations of credit risk, such as foreign exchange contracts, option contracts, or foreign currency hedging arrangements.

Segment Information

We manage our business as one reportable segment consisting of investments in data centers located in the United States. Although we provide services in several markets, these operations have been aggregated into one reportable segment based on the similar economic characteristics amongst all markets, including the nature of the services provided and the type of customers purchasing these services.

Recent Accounting Pronouncements

In September 2011, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2011-08, Intangibles—Goodwill and Other (Topic 350): Testing Goodwill for Impairment. ASU 2011-08 permits an entity to first perform a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If it is determined through the qualitative assessment that a reporting unit’s fair value is more likely than not greater than its carrying value, the remaining impairment steps are unnecessary. The new standard is effective for annual and interim goodwill impairment tests performed for fiscal years beginning after December 15, 2011, with early adoption permitted. The Company adopted the provisions of this standard effective September 30, 2011. The adoption of this standard did not have a material impact on the Company’s consolidated financial statements.

In June 2011, the FASB issued ASU 2011-05, Comprehensive Income (Topic 220): Presentation of Comprehensive Income, which amends current comprehensive income guidance. This accounting update eliminates the option to present the components of other comprehensive income as part of the statement of stockholders’ equity. Instead, the Company must report comprehensive income in either a single continuous statement of comprehensive income which contains two sections, net income and other comprehensive income, or in two separate but consecutive statements. This new guidance is effective for fiscal years and interim periods beginning after December 15, 2011. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements.

Acquisitions

12 Months Ended

Dec. 31, 2011

Acquisitions [Abstract]

Acquisitions

3. Acquisitions

As described in Note 1, we acquired the CoreSite Acquired Properties as part of the Company’s IPO for $316.8 million. In connection with the acquisition of the CoreSite Acquired Properties, we incurred $3.3 million of transaction costs. The results of operations for each of the acquired entities are included in our consolidated statements of operations only from the date of acquisition. The following table reflects the allocation of the purchase price for the entities we acquired on September 28, 2010 (in thousands):

		September 30,
Consideration paid
Issuance of operating partnership units	$	316,836
Allocation of consideration paid to acquire Coresite Acquired Properties
Net investments in real estate	$	334,839
Lease intangibles		82,124
Goodwill		41,191
Mortgage loans payable		(143,863	)
Below-market leases		(15,686	)
Other assets and liabilities acquired, net		18,231

Total allocation of consideration paid	$	316,836

Operating revenues of $21.0 million and an operating loss of $(11.6) million attributed to CoreSite Acquired Properties are included in the consolidated statement of operations for the period from September 28, 2010 to December 31, 2010. If the acquisition of the CoreSite Acquired Properties had occurred on January 1, 2010, the consolidated results of operations for the year ended December 31, 2010 on a pro forma basis would have been as follows (in thousands):

		September 30,
	Year Ended December 31, 2010⁽¹⁾
Revenue	$	144,161
Expenses	$	165,657
Operating loss	$	(21,496	)
Net loss	$	(28,481	)

(1)	These unaudited pro froma results do not purport to be indicative of what operating results would have been had the acquisition occurred on January 1, 2010, and may not be indicative of future operating results.

- Definition

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 88-16
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141
-Paragraph 51, 52
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Appendix F
-Paragraph F4
-Subparagraph e

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 67-73
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6911361&loc=d3e6927-128479

Reference 6: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 805
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-Section 50
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6972119&loc=d3e1383-128463

+ Details

Acquired Intangible Assets and Liabilities

12 Months Ended

Dec. 31, 2011

Acquired Intangible Assets and Liabilities [Abstract]

Acquired Intangible Assets and Liabilities

4. Acquired Intangible Assets and Liabilities

Upon acquisition of real estate, the Company records the intangible assets and liabilities acquired at their estimated fair value separate and apart from goodwill. The Company amortizes identified intangible assets and liabilities that are determined to have finite lives based on the period over which the assets and liabilities are expected to affect, directly or indirectly, the future cash flows of the real estate property acquired (generally the life of the lease). The Company did not add new intangible assets or liabilities during the year ended December 31, 2011. During the year ended December 31, 2010, the Company added approximately $82.1 million of new intangible assets (excluding amount attributed to goodwill) and $15.7 million of new intangible liabilities. The weighted average life of the intangible assets and intangible liabilities acquired during the year ended December 31, 2010 is 3.2 years and 10.8 years, respectively. Amortization of intangibles, for which we are the lessor, related to above or below-market leases is recorded in rental revenue in the consolidated statements of operations. Amortization of other intangibles is recorded in depreciation and amortization in the consolidated statements of operations. Intangible assets subject to amortization are reviewed for impairment whenever events or changes in circumstances indicate that their carrying amount may not be recoverable. An impairment loss is recognized if the carrying amount of an intangible asset is not recoverable and its carrying amount exceeds its estimated fair value. No impairment loss was recognized for the years ended December 31, 2011, 2010, or 2009.

Above-market and below-market lease intangibles balances at December 31, 2011 and 2010 are as follows (in thousands):

		September 30,			September 30,
	December 31,			December 31,
	2011			2010
Lease contracts above-market value	$	8,668		$	8,668
Accumulated amortization		(4,253	)		(1,360	)

Lease contracts above-market value, net	$	4,415		$	7,308

Weighted average remaining life		3.2 years			3.5 years

Lease contracts below-market value	$	21,139		$	21,404
Accumulated amortization		(9,267	)		(4,989	)

Lease contracts below-market value, net	$	11,872		$	16,415

Weighted average remaining life		12.5 years			10.8 years

The net effect of amortization of acquired above-market and below-market leases resulted in an increase to rental income of $1.7 million, $0.4 million, $0.6 million and $1.0 million, for the year ended December 31, 2011, the period from September 28, 2010 to December 31, 2010, the period from January 1, 2010 to September 27, 2010 and the year ended December 31, 2009, respectively. The estimated amortization of acquired below-market leases, net of acquired above-market leases for each of the five succeeding fiscal years, which will be a net increase to rental revenue, is as follows (in thousands):


Year Ending December 31,
2012	$	1,270
2013		780
2014		493
2015		546
2016		563
Thereafter		3,805

Total	$	7,457

Amortization of all other identified intangible assets was $32.2 million, $11.1 million, $0.7 million and $0.8 million, for the year ended December 31, 2011, the period from September 28, 2010 to December 31, 2010, the period from January 1, 2010 to September 27, 2010 and the year ended December 31, 2009, respectively. As of December 31, 2011 and 2010, the weighted average remaining useful life was 3.5 years and 3.2 years, respectively. The estimated amortization of all other identified intangible assets for each of the five succeeding fiscal years is as follows (in thousands):


Year Ending December 31,
2012	$	16,720
2013		7,007
2014		2,956
2015		1,874
2016		1,464
Thereafter		2,207

Total	$	32,228

Investment in Real Estate

12 Months Ended

Dec. 31, 2011

Investment in Real Estate [Abstract]

Investment in Real Estate

5. Investment in Real Estate

The following is a summary of the properties owned and leased at December 31, 2011 (in thousands):


Property Name	Location	Acquisition Date				Buildings and Improvements		Leasehold Improvements		Construction in Progress
Property Name	Location	Acquisition Date		Land		Buildings and Improvements		Leasehold Improvements		Construction in Progress		Total Cost
1656 McCarthy	Milpitas, CA		12/6/2006	$	5,086	$	21,941	$	—	$	29	$	27,056
2901 Coronado	Santa Clara, CA		2/2/2007		3,972		45,172		—		—		49,144
2972 Stender	Santa Clara, CA		2/2/2007		4,442		16,630		—		38,918		59,990
Coronado-Stender Properties	Santa Clara, CA		2/2/2007		11,486		11,967		—		229		23,682
70 Innerbelt	Somerville, MA		4/11/2007		6,100		67,248		—		170		73,518
32 Avenue of the Americas	New York, NY		6/30/2007		—		—		30,895		1		30,896
12100 Sunrise Valley	Reston, VA		12/28/2007		12,100		70,527		—		28,204		110,831
One Wilshire	Los Angeles, CA		9/28/2010		—		—		44,445		912		45,357
900 N. Alameda	Los Angeles, CA		9/28/2010		28,467		105,304		—		468		134,239
55 S. Market	San Jose, CA		9/28/2010		6,863		96,245		—		1,941		105,049
427 S. LaSalle	Chicago, IL		9/28/2010		5,493		55,083		—		2,146		62,722
1275 K Street	Washington, DC		9/28/2010		—		—		5,717		66		5,783
2115 NW 22nd Street	Miami, FL		9/28/2010		729		9,600		—		—		10,329

Total				$	84,738	$	499,717	$	81,057	$	73,084	$	738,596

- Definition

The entire disclosure for long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. This disclosure may include property plant and equipment accounting policies and methodology, a schedule of property, plant and equipment gross, additions, deletions, transfers and other changes, depreciation, depletion and amortization expense, net, accumulated depreciation, depletion and amortization expense and useful lives, income statement disclosures, assets held for sale and public utility disclosures.

+ References + Details

Other Assets

12 Months Ended

Dec. 31, 2011

Other Assets [Abstract]

Other Assets

6. Other Assets

Our other assets consisted of the following, net of amortization and depreciation, if applicable, as of December 31, 2011 and 2010 (in thousands):


	December 31,		December 31,
	2011		2010
Deferred leasing costs	$	11,601	$	7,954
Deferred rent receivable		11,051		6,065
Deferred financing costs		3,607		3,426
Leasehold interests in corporate headquarters		2,719		2,959
Other		4,765		3,502

Total	$	33,743	$	23,906

Deferred leasing costs are amortized as amortization expense on a straight-line basis over the remaining life of the underlying leases. The estimated amortization of deferred leasing costs for each of the five succeeding fiscal years is as follows (in thousands):


Year Ending December 31,
2012	$	2,562
2013		2,079
2014		1,678
2015		1,218
2016		1,078
Thereafter		2,986

Total	$	11,601

Leases

12 Months Ended

Dec. 31, 2011

Leases [Abstract]

Leases

7. Leases

The future minimum lease payments to be received under noncancelable leases in effect at December 31, 2011 are as follows (in thousands):


Year Ending December 31,
2012	$	95,620
2013		76,692
2014		57,974
2015		41,403
2016		31,421
Thereafter		59,399

Total	$	362,509

For the years ended December 31, 2011, 2010 and 2009, total operating revenues recognized from one customer accounted for 11.4%, 16.4%, and 8.5%, respectively. For the years ended December 31, 2011, 2010 and 2009, total operating revenues recognized from another customer accounted for 3.3%, 7.0%, and 19.2%, respectively.

- Definition

The entire disclosure for lessor entity's leasing arrangements for operating, capital and leveraged leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 13
-Paragraph 23
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=6452767&loc=d3e37045-112695

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Debt

12 Months Ended

Dec. 31, 2011

Debt [Abstract]

Debt

8. Debt

A summary of outstanding indebtedness as of December 31, 2011 and 2010 is as follows (in thousands):

	September 30,		September 30,			September 30,			September 30,
	Interest Rate	Maturity Date			December 31, 2011			December 31, 2010
Senior secured credit facility	⁽¹⁾		December 15, 2014		$	5,000	⁽²⁾	$	—
427 S. LaSalle—Senior mortgage loan	LIBOR plus 0.60% (0.88% and 0.86% at December 31, 2011 and 2010)		March 9, 2012			25,000	⁽²⁾		25,000
427 S. LaSalle—Subordinate mortgage loan	LIBOR plus 2.95% (3.21% at December 31, 2010)		N/A			—			5,000
427 S. LaSalle—Mezzanine loan	LIBOR plus 4.83% (5.09% at December 31, 2010)		N/A			—			10,000
55 S. Market	LIBOR plus 3.50% (3.75% and 3.76% at December 31, 2011 and 2010)⁽³⁾		October 9, 2012	⁽⁴⁾		60,000			60,000
12100 Sunrise Valley	LIBOR plus 2.75% (3.06% and 3.01% at December 31, 2011 and 2010)⁽³⁾		June 1, 2013			31,864			25,560

Total principal outstanding						121,864			125,560

Unamortized acquired below-market debt adjustment on 427 S. LaSalle mortgage loans						—			(687	)

Total indebtedness					$	121,864		$	124,873

(1)

At the Company’s election, borrowings under the credit facility bear interest at a rate per annum equal to either (i) LIBOR plus 225 basis points to 300 basis points, or (ii) a base rate plus 125 basis points to 200 basis points, depending on our leverage ratio. As of December 31, 2011, the interest rate on outstanding borrowings under the senior secured credit facility was 2.54%.

(2)	Subsequent to December 31, 2011, the Company completed additional draws totaling $30.3 million on the senior secured credit facility and repaid the senior mortgage loan of $25.0 million secured by the 427 S. LaSalle property which was scheduled to mature on March 9, 2012.

(3)	In October 2010, we entered into an interest rate swap agreement with respect to the indebtedness on 55 S. Market and an interest rate cap agreement with respect to the indebtedness on 12100 Sunrise Valley, each as a cash flow hedge for interest incurred on these LIBOR based loans.

(4)	The mortgage contains one two-year extension option subject to our Company meeting certain financial and other customary conditions and the payment of an extension fee equal to 60 basis points.

Senior Secured Credit Facility

On December 15, 2011, our Operating Partnership and certain subsidiary co-borrowers entered into an amended and restated senior secured revolving credit facility (the “Amended Credit Agreement”) with a group of lenders for which KeyBank National Association acts as the administrative agent. The Amended Credit Agreement amended our Operating Partnership’s then existing senior secured revolving credit facility, dated September 28, 2010 (the “Prior Facility”), and is unconditionally guaranteed on a senior unsecured basis by us. Our Operating Partnership acts as the parent borrower, and our subsidiaries that own 1656 McCarthy, 70 Innerbelt, 2901 Coronado and 900 N. Alameda, are co-borrowers under the Amended Credit Agreement, with borrowings under the facility secured by a lien on these properties on a senior secured basis. In addition, the obligations of each of our Operating Partnership and the co-borrowers under the Amended Credit Agreement are joint and several.

The Amended Credit Agreement increased the commitment from the Prior Facility of $110.0 million to $225.0 million, and extended the initial maturity date of the Prior Facility from September 28, 2013, to December 15, 2014, with a one-time extension option, which, if exercised, would extend the maturity date to December 15, 2015. An exercise of the extension option is subject to the payment of an extension fee equal to 25 basis points of the total commitment under the Amended Credit Agreement at initial maturity and certain other customary conditions. As of December 31, 2011, $5.0 million was outstanding under the facility.

Under the Amended Credit Agreement, our Operating Partnership may elect to have borrowings bear interest at a rate per annum, equal to (i) LIBOR plus 225 basis points to 300 basis points, or (ii) a base rate plus 125 basis points to 200 basis points, each depending on our Operating Partnership’s leverage ratio. The Amended Credit Agreement also contains an accordion feature to allow our Operating Partnership to increase the total commitment by $175.0 million, to $400.0 million, under specified circumstances.

The total amount available for borrowings under the Amended Credit Agreement will be subject to the lesser of a percentage of the appraised value of our Operating Partnership’s properties that form the designated borrowing base properties of the facility, a minimum borrowing base debt service coverage ratio and a minimum borrowing base debt yield. As of December 31, 2011, $144.5 million was available for us to borrow under the facility.

Subsequent to December 31, 2011, we have completed additional draws totaling $30.3 million and repaid the senior mortgage loan of $25.0 million secured by the 427 S. LaSalle property. In conjunction with the repayment of the senior mortgage loan, 427 S. LaSalle was added as a co-borrower under the Amended Credit Agreement, with borrowings under the facility secured by a lien on such real estate property on a senior secured basis. The addition of the 427 S. LaSalle property to the Amended Credit Agreement increased our borrowing capacity to $202.5 million of which $158.6 million was available for us to borrow under the facility.

Our ability to borrow under the Amended Credit Agreement is subject to ongoing compliance with a number of financial covenants and other customary restrictive covenants, including:

•

a maximum leverage ratio (defined as consolidated total indebtedness to total gross asset value) of 60%;

•

a minimum fixed charge coverage ratio (defined as adjusted consolidated earnings before interest, taxes, depreciation and amortization to consolidated fixed charges) of 1.75 times;

•

a maximum unhedged variable rate debt ratio (defined as unhedged variable rate indebtedness to gross asset value) of 30%;

•

a maximum recourse debt ratio (defined as recourse indebtedness other than indebtedness under the revolving credit facility to gross asset value) of 30%; and

•

a minimum tangible net worth equal to at least $468,750,000 plus 80% of the net proceeds of any additional equity issuances.

As of December 31, 2011, we were in compliance with the covenants.

Financing costs of $2.3 million and $1.7 million, which were incurred in connection with the execution of the Prior Facility and the Amended Credit Agreement, respectively, have been capitalized and are included in deferred financing costs. Amortization of these deferred financing costs for year ended December 31, 2011 and 2010 totaled $0.8 million and $0.2 million, respectively, and have been included in interest expense.

427 S. LaSalle

As of December 31, 2011, the 427 S. LaSalle property had a senior mortgage of $25.0 million, which was scheduled to mature on March 9, 2012. This loan was secured by deeds of trust on the property and required payments of interest only until maturity. The mortgage required ongoing compliance by us with various nonfinancial covenants. As of December 31, 2011, we were in compliance with the covenants.

On April 29, 2011, we repaid the $10.0 million mezzanine loan on the 427 S. LaSalle property at a discount. As a result of this discounted payoff, we reduced our debt by $10.0 million, paying $9.5 million in cash and recognizing a $0.5 million gain, net of fees on the transaction.

On June 3, 2011, we repaid the $5.0 million subordinate loan on the 427 S. LaSalle property at a discount. As a result of this discounted payoff, we reduced our debt by $5.0 million, paying $4.6 million in cash and recognizing a $0.4 million gain, net of fees on the transaction.

On February 7, 2012, we repaid the $25.0 million senior mortgage loan on the 427 S. LaSalle property.

55 S. Market

As of December 31, 2011, the 55 S. Market property had a $60.0 million mortgage loan, which matures on October 9, 2012. The loan contains one two-year extension option provided we meet certain financial and other customary conditions and subject to the payment of an extension fee equal to 60 basis points. The loan bears interest at LIBOR plus 350 basis points and requires the payment of interest only until maturity. The loan requires ongoing compliance by us with various covenants including liquidity and net operating income covenants. As of December 31, 2011, we were in compliance with the covenants.

On October 7, 2010, we entered into a $60.0 million interest rate swap agreement to protect against adverse fluctuations in interest rates by reducing our exposure to variability in cash flows relating to interest payments on the $60.0 million 55 S. Market mortgage. The interest rate swap matures on October 9, 2012 and effectively fixes the interest rate at 4.01%.

12100 Sunrise Valley

As of December 31, 2011, the 12100 Sunrise Valley property had a mortgage of $31.9 million. The loan is secured by the 12100 Sunrise Valley property and required payments of interest only until the “amortization commencement date” on July 1, 2011. The loan matures on June 1, 2013, and we may exercise the one-year extension option provided we meet certain financial and other customary conditions and subject to the payment of an extension fee equal to 50 basis points. The loan contains certain financial and nonfinancial covenants. As of December 31, 2011, we were in compliance with the covenants.

On October 8, 2010, we purchased an interest rate cap to hedge $25.0 million of the indebtedness secured by our 12100 Sunrise Valley property. The interest rate cap matures on October 1, 2012 and hedges against LIBOR interest rate increases above 2.0%.

Debt Maturities

The following table summarizes our debt maturities and principal payments as of December 31, 2011 (in thousands):

		September 30,
Year Ending December 31,
2012	$	85,324	⁽¹⁾
2013		31,540
2014		5,000
2015		—
2016		—
Thereafter		—

Total	$	121,864

(1)	On February 7, 2012, we repaid the $25.0 million senior mortgage loan on the 427 S. LaSalle property.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References + Details

Derivatives and Hedging Activities

12 Months Ended

Dec. 31, 2011

Derivatives and Hedging Activities [Abstract]

Derivatives and Hedging Activities

9. Derivatives and Hedging Activities

Risk Management Objective of Using Derivatives

The Company is exposed to certain risk arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its debt funding and the use of derivative financial instruments. Specifically, the Company enters into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The Company’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments principally related to the Company’s investments and borrowings.

Cash Flow Hedges of Interest Rate Risk

The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps and caps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. Interest rate caps designated as cash flow hedges involve the receipt of variable amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an up-front premium.

The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in accumulated other comprehensive income and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. During the period, such derivatives were used to hedge the variable cash flows associated with existing variable-rate debt. The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. During the years ended December 31, 2011, 2010 and 2009, the Company did not record any amount in earnings related to derivatives due to hedge ineffectiveness.

Amounts reported in accumulated other comprehensive income related to derivatives will be reclassified to interest expense as interest payments are made on the Company’s variable-rate debt. During 2012, the Company estimates that $0.1 million will be reclassified as an increase to interest expense.

As of December 31, 2011, the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk:

Cash Flow Hedge Derivative Summary

		September 30,		September 30,
	Number of Instruments		Notional
Derivative type
Interest rate swap		1	$	60,000,000
Interest rate cap		1		25,000,000

Total		2	$	85,000,000

Non-designated Hedges

Additionally, the Company does not use derivatives for trading or speculative purposes. Derivatives not designated as hedges are not speculative and are used to manage the Company’s exposure to interest rate movements but due to immateriality, are not designated for hedge accounting purposes. The Company’s derivatives detailed in the table below are not designated as hedging instruments for accounting purposes and do not have material economic value as of December 31, 2011. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings. As of December 31, 2011, the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships:

Non-Designated Derivative Summary

		September 30,		September 30,
	Number of Instruments		Notional
Derivative type
Interest rate caps		2	$	40,000,000

Total		2	$	40,000,000

Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet

The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the balance sheet as of December 31, 2011 and 2010.

		September 30,		September 30,		September 30,		September 30,
	Fair Values of Derivative Instruments
	Derivative Assets				Derivative Liabilities
	As of December 31,
	2011		2010		2011		2010
	(In thousands)
Derivatives designated as hedging instruments
Balance sheet location		Other Assets		Other Assets		Other Liabilities		Other Liabilities
Interest rate caps	$	—	$	31	$	—	$	—
Interest rate swaps		—		117		50		—

Total	$	—	$	148	$	50	$	—

Derivatives not designated as hedging instruments
Balance sheet location		Other Assets		Other Assets		Other Liabilities		Other Liabilities
Interest rate caps	$	—	$	—	$	—	$	—

Total	$	—	$	—	$	—	$	—

Tabular Disclosure of the Effect of Derivative Instruments on the Income Statement

The tables below present the effect of the Company’s derivative financial instruments on the statement of operations for the years ended December 31, 2011, 2010 and 2009 (in thousands).

		XXXXX			XXXXX		XXXXX	XXXXX		XXXXX			XXXXX		XXXXX	XXXXX		XXXXX		XXXXX		XXXXX
	Income Statement Impact of Derivatives in Cash Flow Hedging Relationships
	Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)							Location of Gain or (Loss) Reclassified from Accumulated OCI into Income	Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)							Location of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness	Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)
	2011			2010		2009		(Effective Portion)	2011			2010		2009		Testing)	2011		2010		2009
Interest rate derivative
Interest rate caps	$	(30	)	$	4	$	—	Interest income/ (expense)	$	(5	)	$	—	$	—	Other income/ (expense)	$	—	$	—	$	—
Interest rate swap		(336	)		95		—	Interest income/ (expense)		(168	)		22		—	Other income/ (expense)		—		—		—

Total	$	(366	)	$	99	$	—		$	(173	)	$	22	$	—		$	—	$	—	$	—

Credit-Risk-Related Contingent Features

The Company has agreements with each of its derivative counterparties that contain a provision under which if the Company defaults on any of its indebtedness, including default when repayment of the indebtedness has not been accelerated by the lender, the Company could also be declared in default on its derivative obligations. Such a default may require the Company to settle any outstanding derivatives at their then current fair value. As of December 31, 2011, the derivative instruments with fair values in a net liability position were not material and the Company has not posted any cash collateral related to these agreements.

- Definition

The entire disclosure for the entity's entire derivative instruments and hedging activities. Describes an entity's risk management strategies, derivatives in hedging activities and non-hedging derivative instruments, the assets, obligations, liabilities, revenues and expenses arising therefrom, and the amounts of and methodologies and assumptions used in determining the amounts of such items.

+ References

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-Name Statement of Financial Accounting Standard (FAS)
-Number 133
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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+ Details

Noncontrolling Interests Operating Partnership

12 Months Ended

Dec. 31, 2011

Noncontrolling Interests Operating Partnership [Abstract]

Noncontrolling Interests Operating Partnership

10. Noncontrolling Interests — Operating Partnership

Noncontrolling interests represent the limited partnership interests in the Operating Partnership held by individuals and entities other than CoreSite Realty Corporation. Since September 28, 2011, the current holders of Operating Partnership units have been eligible to have the Operating Partnership units redeemed for cash or, at our option, exchangeable into our common stock on a one-for-one basis. We have evaluated whether we control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the share settlement of the Operating Partnership units. Based on the results of this analysis, we concluded that the Operating Partnership units met the criteria to be classified within equity at December 31, 2011 and 2010.

The following table shows the ownership interests in the Operating Partnership as of December 31, 2011 and 2010:

		September 30,		September 30,			September 30,		September 30,
	December 31, 2011					December 31, 2010
	Number of Units		Percentage of Total			Number of Units		Percentage of Total
The Company		20,404,743		44.6	%		19,458,605		42.6	%
Noncontrolling interests consist of:
Common units held by third parties		25,275,390		55.2	%		26,165,000		57.3	%
Incentive units held by employees		69,692		0.2	%		61,065		0.1	%

Total		45,749,825		100.0	%		45,684,670		100.0	%

For each share of common stock issued by the Company, the Operating Partnership issues an equivalent Operating Partnership unit to the Company. During the year ended December 31, 2011, the Company issued 56,528 shares of common stock related to employee compensation arrangements and therefore an equivalent number of Operating Partnership units were issued.

Additionally, during the year ended December 31, 2011, 8,627 Operating Partnership units were issued to employees upon their vesting in the incentive unit awards.

On November 15, 2011, 889,610 Operating Partnership units held by third parties were redeemed for common stock of the Company. This redemption was recorded as a $13.8 million reduction to noncontrolling interests in the Operating Partnership and an increase to common stock and additional paid in capital.

The redemption value of the noncontrolling interests at December 31, 2011 was $451.6 million based on the closing price of the Company’s stock of $17.82 on that date.

- Definition

The entire disclosure for noncontrolling interest in consolidated subsidiaries, which could include the name of the subsidiary, the ownership percentage held by the parent, the ownership percentage held by the noncontrolling owners, the amount of the noncontrolling interest, the location of this amount on the balance sheet (when not reported separately), an explanation of the increase or decrease in the amount of the noncontrolling interest, the noncontrolling interest share of the net Income or Loss of the subsidiary, the location of this amount on the income statement (when not reported separately), the nature of the noncontrolling interest such as background information and terms, the amount of the noncontrolling interest represented by preferred stock, a description of the preferred stock, and the dividend requirements of the preferred stock.

+ References + Details

Stockholders Equity

12 Months Ended

Dec. 31, 2011

Stockholders' Equity [Abstract]

Stockholders' Equity

11. Stockholders’ Equity

During the year ended December 31, 2011, we issued 263,393 shares of restricted stock and options to purchase 543,380 shares of common stock to certain employees in connection with our 2010 equity incentive plan. Additionally, for their services as members of the Board of Directors, the independent directors not affiliated with the Carlyle Group were each issued 2,520 restricted stock units.

On September 28, 2010, we completed our IPO which resulted in the sale of 19,435,000 shares of our common stock, including 2,535,000 shares as a result of the underwriters exercising their over-allotment option, at a price per share of $16.00, generating gross proceeds to the Company of $311.0 million. The proceeds to the Company, net of underwriters’ discounts, commissions and other offering costs were $285.6 million. Underwriters’ discounts, commissions and other offering costs of $25.3 million are reflected as a reduction to additional paid-in capital in the consolidated balance sheet of the Company.

In connection with the IPO, we issued 6,758 fully vested shares of common stock to certain employees which resulted in a charge to compensation expense of $0.1 million. Additionally, we issued 108,787 shares of restricted stock and 577,555 options to purchase shares of our common stock to certain employees that vest evenly over four years commencing on September 28, 2011. We issued an additional 59,820 restricted shares to employees that vest evenly over a three year period commencing on September 28, 2011.

Upon closing of the IPO, the Company retired the former profits interest incentive program, under which employees were provided equity-based awards in order to align their interests with those of our equity holders and for retention purposes. In retirement of this plan, the Company issued 15,847 fully vested shares of common stock, 10,203 shares of restricted stock which vest evenly over three years commencing on the first anniversary of the IPO, and 6,627 shares of restricted stock which vested in 2011. In addition, certain employees were issued 61,065 fully vested Operating Partnership units and 25,883 unvested Operating Partnership units which vest evenly over three years commencing on September 28, 2011.

During the year ended December 31, 2010, the independent directors not affiliated with the Carlyle Group were issued 10,000 restricted stock units and a one-time grant of 10,000 options to purchase shares of our common stock for their services as members of the Board of Directors.

We have declared the following dividends on our common stock and equivalent distributions on units in our Operating Partnership for the years ended December 31, 2011 and 2010:

		September 30,			September 30,		September 30,		September 30,
Record Date	Payment Date			Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
3/31/2011		4/15/2011		$	0.13	$	0.13	$	—
6/30/2011		7/15/2011			0.13		0.13		—
9/30/2011		10/17/2011			0.13		0.13		—
12/31/2011		1/17/2012	⁽¹⁾		0.18		0.18		—

				$	0.57	$	0.57	$	—


12/31/2010		1/14/2011	⁽²⁾	$	0.13	$	0.13	$	—

(1)	The $0.1800 quarterly dividend paid in January 2012 is included as 2011 taxable common dividends.

(2)	Of the $0.1300 quarterly dividend paid in January of 2011, $0.0415 is included as 2010 taxable common dividends and $0.0885 is included as 2011 taxable common dividends.

- Definition

The entire disclosure for shareholders' equity, comprised of portions attributable to the parent entity and noncontrolling interest, if any, including other comprehensive income (as applicable). Including, but not limited to: (1) balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings; (2) accumulated balance for each classification of other comprehensive income and total amount of comprehensive income; (3) amount and nature of changes in separate accounts, including the number of shares authorized and outstanding, number of shares issued upon exercise and conversion, and for other comprehensive income, the adjustments for reclassifications to net income; (4) rights and privileges of each class of stock authorized; (5) basis of treasury stock, if other than cost, and amounts paid and accounting treatment for treasury stock purchased significantly in excess of market; (6) dividends paid or payable per share and in the aggregate for each class of stock for each period presented; (7) dividend restrictions and accumulated preferred dividends in arrears (in aggregate and per share amount); (8) retained earnings appropriations or restrictions, such as dividend restrictions; (9) impact of change in accounting principle, initial adoption of new accounting principle and correction of an error in previously issued financial statements; (10) shares held in trust for Employee Stock Ownership Plan (ESOP); (11) deferred compensation related to issuance of capital stock; (12) note received for issuance of stock; (13) unamortized discount on shares; (14) description, terms, and number of warrants or rights outstanding; (15) shares under subscription and subscription receivables, effective date of new retained earnings after quasi-reorganization and deficit eliminated by quasi-reorganization and, for a period of at least ten years after the effective date, the point in time from which the new retained dates; and (16) retroactive effective of subsequent change in capital structure.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Regulation S-X (SX)
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-Article 4
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 1
-Section B
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Article 4

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
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-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 10: http://www.xbrl.org/2003/role/presentationRef
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-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

Reference 11: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

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Reference 14: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 21: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 22: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Paragraph 1
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Reference 23: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187143-122770

+ Details

Equity Incentive Plan

12 Months Ended

Dec. 31, 2011

Equity Incentive Plan [Abstract]

Equity Incentive Plan

12. Equity Incentive Plan

In connection with our IPO, the Company’s Board of Directors adopted the 2010 equity incentive plan, which we refer to as the 2010 Plan. The 2010 Plan is administered by the Board of Directors, or the plan administrator. Awards issuable under the 2010 Plan include common stock, stock options, restricted stock, stock appreciation rights, dividend equivalents and other incentive awards. We have reserved a total of 3,000,000 shares of our common stock for issuance pursuant to the 2010 Plan, which may be adjusted for changes in our capitalization and certain corporate transactions. To the extent that an award expires, terminates or lapses, or an award is settled in cash without the delivery of shares of common stock to the participant, then any unexercised shares subject to the award will be available for future grant or sale under the 2010 Plan. Shares of restricted stock which are forfeited or repurchased by us pursuant to the 2010 Plan may again be optioned, granted or awarded under the 2010 Plan. The payment of dividend equivalents in cash in conjunction with any outstanding awards will not be counted against the shares available for issuance under the 2010 Plan.

Stock Options

Stock option awards are granted with an exercise price equal to the closing market price of the Company’s common stock at the date of grant. The fair value of each option granted under the 2010 Plan is estimated on the date of the grant using the Black-Scholes option-pricing model. The fair values are being expensed on a straight-line basis over the vesting period.

No stock option awards were issued during the year ended December 31, 2009.The following table sets forth the 2010 Plan’s stock option activity for the years ended December 31, 2011 and 2010:

		September 30,			September 30,		September 30,		September 30,
	Number of Shares Subject to Option			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
Options outstanding, December 31, 2009		—		$	—
Granted		587,555			16.00
Forfeited		—			—
Expired		—			—
Exercised		—			—

Options outstanding, December 31, 2010		587,555			16.00		9.7 years	$	—
Granted		543,380			15.27
Forfeited		(122,848	)		15.80
Expired		(8,074	)		16.00
Exercised		(1,962	)		16.00			Less than $	0.1 million

Options outstanding, December 31, 2011		998,051		$	15.63		8.9 years	$	2.2 million


Exercisable at December 31,
2011		130,942		$	16.00		8.7 years	$	0.2 million
2010		—			N/A		N/A		N/A

The following table sets forth the number of shares subject to option that are unvested as of December 31, 2011 and the fair value of these options at the grant date:

		September 30,			September 30,
	Number of Shares Subject to Option			Weighted Average Fair Value at Grant
Unvested balance, December 31, 2009		—		$	—
Granted		587,555			4.95
Forfeited		—			—
Vested		—			—

Unvested balance, December 31, 2010		587,555			4.95
Granted		543,380			4.89
Forfeited		(122,848	)		4.93
Vested		(140,978	)		4.92

Unvested balance, December 31, 2011		867,109		$	4.92

As of December 31, 2011, total unearned compensation on options was approximately $3.3 million, and the weighted average vesting period was 3.0 years. The fair value of each option award is estimated on the date of grant using a Black-Scholes option valuation model. As the Company has been a publicly traded company only since September 28, 2010, expected volatilities used in the Black-Scholes model are based on the historical volatility of a group of comparable REITs. We utilize the simplified method of estimating the term for options granted due to the lack of historical exercise data necessary to provide a reasonable basis upon which to estimate the term. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. The following table summarizes the assumptions used to value the stock options granted during the years ended December 31, 2011 and 2010:

		September 30,			September 30,
	2011			2010
Expected term (in years)		6.25			6.25
Expected volatility		43.07	%		43.59	%
Expected annual dividend		3.41	%		3.25	%
Risk-free rate		2.76	%		1.33	%

Restricted Awards

During the years ended December 31, 2011 and 2010, the Company issued 263,393 and 185,437 shares of restricted stock, respectively, which had values of $4.0 million and $3.0 million, respectively, on the grant date. Also during the years ended December 31, 2011 and 2010, the Company issued 10,080 and 10,000 restricted stock units or RSUs, respectively, which had values of $0.2 million and $0.2 million, respectively, on the grant date. The principal difference between these instruments is that RSUs are not shares of the Company’s common stock and do not have any of the rights or privileges thereof, including voting rights. On the applicable vesting date, the holder of an RSU becomes entitled to a share of common stock. The restricted awards will be amortized on a straight-line basis to expense over the vesting period. The following table sets forth the number of unvested restricted awards and the weighted average fair value of these awards at the date of grant:

		September 30,			September 30,
	Restricted Awards			Weighted Average Fair Value at Grant
Unvested balance, December 31, 2009		—		$	—
Granted		195,437			15.98
Forfeited		—			—
Vested		—			—

Unvested balance, December 31, 2010		195,437			15.98
Granted		273,473			15.19
Forfeited		(51,213	)		15.81
Vested		(74,466	)		16.10

Unvested balance, December 31, 2011		343,231		$	15.35

As of December 31, 2011, total unearned compensation on restricted awards was approximately $4.0 million, and the weighted average vesting period was 2.8 years.

Operating Partnership Units

In connection with the IPO, we issued 25,883 Operating Partnership units, which were fair valued at $15.98 per unit or $0.4 million in total. The Operating Partnership units will be amortized on a straight-line basis to expense over the vesting period. As of December 31, 2011, 8,627 units have vested and 17,256 units were unvested. As of December 31, 2011, total unearned compensation on Operating Partnership units was approximately $0.2 million, and the weighted average vesting period was 1.8 years.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64, 65, A240
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 93-6
-Paragraph 53
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 50
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5444-113901

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

+ Details

Earnings Per Share

12 Months Ended

Dec. 31, 2011

Earnings Per Share [Abstract]

Earnings Per Share

13. Earnings Per Share

Basic loss per share is calculated by dividing the net loss attributable to common shares by the weighted average number of common shares outstanding during the period. Diluted loss per share adjusts basic loss per share for the effects of potentially dilutive common shares, if the effect is not antidilutive. Potentially dilutive common shares consist of shares issuable under our equity-based compensation plan and Operating Partnership units. For the years ended December 31, 2011 and 2010, 998,051 and 587,555 options to purchase common stock, respectively, and 343,231 and 195,437 restricted shares, respectively, have been excluded from the calculation of diluted earnings per share as their effect would have been antidilutive.

Employee Benefit Plan

12 Months Ended

Dec. 31, 2011

Employee Benefit Plan [Abstract]

Employee Benefit Plan

14. Employee Benefit Plan

CoreSite, LLC has a tax qualified retirement 401(k) plan that provides employees with an opportunity to save for retirement on a tax advantaged basis. Employees may participate after six months of employment. Additionally at that time, the Company provides a safe harbor contribution equal to 3% of the participant’s annual salary. The employee and employer contributions are limited to the maximum amount allowed by the Internal Revenue Service. Both employee and employer contributions vest immediately. For the years ended December 31, 2011and 2010, the Company contributions were $0.4 million and less than $0.1 million, respectively.

Estimated Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2011

Estimated Fair Value of Financial Instruments [Abstract]

Estimated Fair Value of Financial Instruments

15. Estimated Fair Value of Financial Instruments

Authoritative guidance issued by the FASB establishes a hierarchy of valuation techniques based on the observability of inputs utilized in measuring assets and liabilities at fair values. This hierarchy establishes market-based or observable inputs as the preferred source of values, followed by valuation models using management assumptions in the absence of market inputs. The three levels of the hierarchy under the authoritative guidance are as follows:

Level 1 — Inputs are quoted prices in active markets for identical assets or liabilities.

Level 2 — Inputs are quoted prices for similar assets or liabilities in an active market, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable, and market-corroborated inputs which are derived principally from or corroborated by observable market data.

Level 3 — Inputs are derived from valuation techniques in which one or more significant inputs or value drivers are unobservable.

Our financial instruments consist of cash and cash equivalents, restricted cash, accounts and other receivables, interest rate caps, interest rate swaps, senior secured credit facility, mortgage loans payable, interest payable and accounts payable. The carrying values of cash and cash equivalents, restricted cash, accounts and other receivables, senior secured credit facility, interest payable and accounts payable approximate fair values due to the short-term nature of these accounts. The interest rate caps and interest rate swap are carried at fair value.

The combined balance of our mortgage loans payable was $116.9 million and $125.6 million as of December 31, 2011 and 2010 (excluding a $0.7 million fair value of acquired debt adjustment as of December 31, 2010), respectively, with a fair value of $116.1 million and $123.8 million, respectively, based on Level 3 inputs from the fair value hierarchy. The fair values of mortgage notes payable are based on the Company’s assumptions of interest rates and terms available incorporating the Company’s credit risk.

Measurements of asset retirement obligations upon initial recognition are based on Level 3 inputs. The significant unobservable inputs to this fair value measurement include estimates of remediation costs, inflation rate, market risk premium and the expected timing of development or redevelopment. The inputs are derived based on historical data as well as management’s best estimate of current costs.

Derivative financial instruments

Currently, the Company uses interest rate swaps to manage interest rate risk. The fair value of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based the expectation of future interest rates (forward curves) derived from observed market interest rate curves. In addition, to comply with the provisions of FASB ASC 820, credit valuation adjustments, which consider the impact of any credit enhancements to the contracts, are incorporated in the fair values to account for potential nonperformance risk. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered any applicable credit enhancements such as collateral postings, thresholds, mutual puts, and guarantees.

Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of December 31, 2011 and 2010, the Company assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustment is not significant to the overall valuation of its derivative portfolios. As a result, the Company classifies its derivative valuations in Level 2 of the fair value hierarchy.

The table below presents the Company’s assets and liabilities measured at fair value on a recurring basis as of December 31, 2011 and 2010, aggregated by the level in the fair value hierarchy within which those measurements fall.

		September 30,		September 30,		September 30,		September 30,		September 30,		September 30,		September 30,		September 30,
	Recurring Fair Value Measurements
	Quoted Prices in Active Markets for Identical Assets and Liabilities				Significant Other Observable Inputs				Significant Unobservable Inputs
	(Level 1)				(Level 2)				(Level 3)				Total Fair Value
	As of December 31,				As of December 31,				As of December 31,				As of December 31,
	2011		2010		2011		2010		2011		2010		2011		2010
	(In thousands)
Assets
Derivative Financial Instruments	$	—	$	—	$	—	$	148	$	—	$	—	$	—	$	148

Liabilities
Derivative Financial Instruments	$	—	$	—	$	50	$	—	$	—	$	—	$	50	$	—

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44A, 44B
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15C, 15D
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15A
-Subparagraph a-d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15B
-Subparagraph a, b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 3, 10, 14, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32, 33, 34
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 17-22, 27, 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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-Name Accounting Standards Codification
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Reference 11: http://www.xbrl.org/2003/role/presentationRef
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Reference 12: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
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-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19296-110258

+ Details

Related Party Transactions

12 Months Ended

Dec. 31, 2011

Related Party Transactions

16. Related Party Transactions

Prior to the closing of the IPO on September 28, 2010, CoreSite, LLC was engaged to act as the Company’s agent for the purpose of coordinating the activities of the property manager, for leasing and servicing the properties, and for overseeing property build-out activities. Subsequent to our Predecessor’s acquisition of CoreSite, LLC as part of the IPO on September 28, 2010, all related party revenue and expenses incurred in connection with CoreSite, LLC’s activities, have been eliminated in consolidation. For the years ended December 31, 2010 and 2009, CoreSite, LLC earned management fees from the Predecessor of $3.6 million and $2.2 million, respectively. For the years ended December 31, 2010 and 2009, CoreSite, LLC earned lease commissions from our Predecessor of $2.8 million and $1.8 million, respectively. These commissions are included in deferred leasing costs. For the years ended December 31, 2010 and 2009, CoreSite, LLC earned construction management fees from our Predecessor of $1.2 million and $0.6 million, respectively. The construction management fees are included in building improvements and construction in progress. For the years ended December 31, 2010 and 2009, CoreSite, LLC was reimbursed for payroll related expenses from our Predecessor of $1.2 million and $1.0 million, respectively. At December 31, 2011 and 2010, none of the fees were payable to CoreSite, LLC.

We lease 1,515 net rentable square feet of space at our 12100 Sunrise Valley property to an affiliate of The Carlyle Group. The lease commenced on July 1, 2008 and expires on June 30, 2013. Rental revenue was $0.2 million, $0.2 million and less than $0.2 million for the years ended December 31, 2011, 2010 and 2009, respectively.

- Definition

The entire disclosure for related party transactions, including the nature of the relationship(s), a description of the transactions, the amount of the transactions, the effects of any change in the method of establishing the terms of the transaction from the previous period, stated interest rate, expiration date, terms and manner of settlement per the agreement with the related party, and amounts due to or from related parties. If the entity and one or more other entities are under common ownership or management control and this control affects the operating results or financial position, disclosure includes the nature of the control relationship even if there are no transactions between the entities. Disclosure may also include the aggregate amount of current and deferred tax expense for each statement of earnings presented where the entity is a member of a group that files a consolidated tax return, the amount of any tax related balances due to or from affiliates as of the date of each statement of financial position presented, the principal provisions of the method by which the consolidated amount of current and deferred tax expense is allocated to the members of the group and the nature and effect of any changes in that method. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 4
-Section 08
-Paragraph k

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Number 210
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-Name Statement of Financial Accounting Standard (FAS)
-Number 57
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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+ Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2011

Commitments and Contingencies [Abstract]

Commitments and Contingencies

17. Commitments and Contingencies

The Company currently leases the data center space under noncancelable operating lease agreements at 32 Avenue of the Americas, One Wilshire and 1275 K Street, and the Company leases its headquarters located in Denver, Colorado under a noncancelable operating lease agreement. The lease agreements provide for base rental rate increases at defined intervals during the term of the lease. In addition, the Company has negotiated rent abatement periods to better match the phased build-out of the data center space. The Company accounts for such abatements and increasing base rentals using the straight-line method over the noncancelable term of the lease. The difference between the straight-line expense and the cash payment is recorded as deferred rent payable.

Additionally, the Company has commitments related to telecommunications capacity used to connect data centers located within the same market or geographical area and power usage.

The following table summarizes our contractual obligations as of December 31, 2011 (in thousands):

		September 30,		September 30,		September 30,		September 30,		September 30,		September 30,		September 30,
	2012		2013		2014		2015		2016		Thereafter		Total
Operating leases	$	17,044	$	17,457	$	17,742	$	17,620	$	17,370	$	26,885	$	114,118
Other⁽¹⁾		5,186		1,384		261		157		142		887		8,017

Total	$	22,230	$	18,841	$	18,003	$	17,777	$	17,512	$	27,772	$	122,135

(1)	Obligations for tenant improvement work at 55 S. Market Street, power contracts, telecommunications leases and insurance premiums.

Rent expense was $18.3 million, $4.6 million, $2.2 million and $2.8 million, for the year December 31, 2011, for the period from September 28, 2010 to December 31, 2010, the period from January 1, 2010 to September 27, 2010 and the year ended December 31, 2009, respectively.

Our properties require periodic investments of capital for general capital improvements and for tenant related capital expenditures. Additionally, the Company enters into various construction contracts with third parties for the development and redevelopment of our properties. At December 31, 2011, we had open commitments related to construction contracts of approximately $8.0 million.

From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. Management believes that the resolution of such matters will not have a material adverse effect on the financial position, results of operations or cash flows of the Company.

Prior to the completion of our IPO, Ari Brumer, the former general counsel of our affiliate CoreSite, LLC, filed suit in federal court in Colorado against the Company, certain of our affiliates, our chief executive officer and certain affiliates of the Funds and Carlyle. In his complaint, Mr. Brumer alleged that he was fraudulently induced to accept employment with CoreSite, LLC, and that his employment was terminated in retaliation for his assertions that the Company and certain of its officers and affiliates had been involved in or committed certain illegal or improper acts. We investigated the assertions of illegal or improper acts made by Mr. Brumer at that time, and we concluded that those assertions were not based on, or supported by, facts.

On September 28, 2010, Mr. Brumer voluntarily dismissed the federal court action without prejudice and filed a substantially identical complaint in Colorado state court in Denver. In the state action, Mr. Brumer claims actual damages in an amount to be proven at trial, non-economic damages, special damages of $1,019,000 principally attributable to real estate losses that he allegedly incurred from relocating to Colorado, punitive damages, attorneys’ fees and costs. On January 11, 2011, the Court dismissed one of Mr. Brumer’s claims as legally insufficient and ordered the dismissal of all claims against our chief executive officer individually. Mr. Brumer subsequently filed an amended complaint.

On March 8, 2011, the Company filed its answer to the amended complaint and asserted counterclaims against Mr. Brumer, alleging that he attempted to disrupt the Company’s initial public offering for his personal advantage after his employment was terminated by the Company. On May 25, 2011, Mr. Brumer filed a second amended complaint and jury demand, adding a claim for defamation based on the Company’s disclosure in a public filing of the allegations made by the Company in its counterclaims. The case is set for a nine-day trial to commence on October 1, 2012.

Because the case is still in the preliminary stage of discovery, the cost of the litigation and its ultimate resolution are not estimable at this time. We believe that we have valid defenses to Mr. Brumer’s remaining claims and that there is significant merit to our counterclaims against Mr. Brumer. We intend to vigorously defend the case and pursue our counterclaims against Mr. Brumer. Based on the information currently available, we continue to believe that the litigation will not have a material adverse effect on our business, financial position or liquidity.

One of our former customers, Add2Net, Inc., brought an action against us in April of 2009 before the American Arbitration Association in California asserting claims of breach of contract, unfair business practices, negligent misrepresentation and fraudulent inducement. Add2Net alleges that it has suffered damages of approximately $3.5 million, consisting of license and service fees paid to us, loss of business income and equipment damage, and seeks attorney’s fees and punitive damages. We have counterclaimed for breach of contract and bad faith dealing on account of $1.25 million in unpaid license and service fees, plus attorney’s fees. We believe that we have valid defenses to Add2Net’s claims and that our claims for unpaid license and service fees are valid and justified. We intend to vigorously defend the claims against us and pursue the counterclaims for our unpaid license and service fees.

Because discovery has yet to be completed in the arbitration, the cost of the litigation and its ultimate resolution are not estimable at this time. Based on the information currently available, however, we do not believe that it will have a material adverse effect on our business, financial position or liquidity.

- Definition

The entire disclosure for commitments and contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 14
-Paragraph 3
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Name Accounting Standards Codification
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+ Details

Quarterly Financial Information

12 Months Ended

Dec. 31, 2011

Quarterly Financial Information [Abstract]

Quarterly Financial Information

18. Quarterly Financial Information (unaudited)

The table below reflects the selected quarterly information for the years ended December 31, 2011 and 2010 (in thousands except share data):

		September 30,		September 30,		September 30,			September 30,
	The Company
	Three Months Ended
	December 31, 2011		September 30, 2011		June 30, 2011			March 31, 2011
Revenue	$	46,029	$	44,367	$	42,484		$	39,966
Operating income (loss)		1,072		1,125		(3,473	)		(5,814	)
Net income (loss)		462		263		(3,588	)		(7,916	)
Net income (loss) attributable to common shares		179		112		(1,530	)		(3,372	)
Net income (loss) per share attributable to common shares—basic	$	0.01	$	0.01	$	(0.08	)	$	(0.17	)

Net income (loss) per share attributable to common shares—diluted	$	0.01	$	0.01	$	(0.08	)	$	(0.17	)

		September 30,			September 30,			September 30,		September 30,
	The Company			The Predecessor
	For the period September 28, 2010 through December 31, 2010			For the period July 1, 2010 through September 27, 2010			Three Months Ended
	For the period September 28, 2010 through December 31, 2010			For the period July 1, 2010 through September 27, 2010			June 30, 2010		March 31, 2010
Revenue	$	38,352		$	14,139		$	12,387	$	9,031
Operating income (loss)		(8,697	)		(913	)		1,344		(398	)
Net income (loss)		(10,722	)		(1,591	)		945		(909	)
Net income (loss) attributable to common shares		(3,351	)		N/A