Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating activities
Net loss	$ (4,209)	$ (3,534)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,535	824
Stock-based compensation	1,699	947
Change in fair value of warrants		(28)
Provision for reserves on accounts receivable	27	67
Amortization of premium on investments	34
Amortization of deferred financing costs		44
Loss on disposal of equipment	1	83
Changes in assets and liabilities:
Accounts receivable	(2,717)	(1,377)
Prepaid expenses and other current assets	(1,168)	(599)
Other assets	20	299
Accounts payable	819	(636)
Accrued expenses	(1,958)	135
Deferred revenue	3,103	1,006
Net cash used in operating activities	(2,814)	(2,769)
Investing activities
Maturities of investments	2,800
Purchases of property and equipment	(126)	(3,742)
Capitalization of internal-use software costs		(24)
Decrease in restricted cash	60
Net cash provided by (used in) investing activities	2,734	(3,766)
Financing activities
Proceeds from exercise of stock options	108	181
Purchase of non-controlling interest in consolidated subsidiary	(1,084)
Proceeds from issuance of common stock in connection with initial public offering, net of offering costs		56,923
Payments under term loan		(7,000)
Net cash (used in) provided by financing activities	(976)	50,104
Effect of exchange rate changes on cash	(559)	(149)
Net (decrease) increase in cash and cash equivalents	(1,615)	43,420
Cash and cash equivalents at beginning of period	21,708	17,227
Cash and cash equivalents at end of period	20,093	60,647
Supplemental disclosure of non-cash financing activities
Conversion of preferred stock to common stock		106,451
Conversion of warrants to purchase preferred stock to warrants to purchase common stock		395
Accretion of Series A, B, C and D redeemable convertible preferred stock issuance costs and dividends		773
Vesting of restricted stock	$ 8	$ 25