Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (7,030)		$ (9,231)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	1,312		1,123
Stock-based compensation	3,596		1,154
Revaluation of convertible preferred stock warrant liability			154
Amortization of premiums/accretion of discounts on short-term investments	337
Changes in operating assets and liabilities:
Accounts receivable, net	(983)		(2,289)
Inventory	129		(100)
Prepaid expenses and other assets	(1,134)		(159)
Accounts payable	196		59
Accrued compensation and benefits	2,616		728
Accrued and other liabilities	(587)		(963)
Severance pay (net)	305		44
Deferred revenue	5,373		4,343
Deferred tax assets	(4)		2
Other	15		79
Net cash provided by (used in) operating activities	4,141		(5,056)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of short-term investments	(50,744)		(988)
Proceeds from sales/maturities of short-term investments	6,928		2,266
Purchase of property and equipment	(1,758)		(1,036)
Purchase of other assets	(400)
Change in restricted cash	96		159
Net cash provided by (used in) investing activities	(45,878)		401
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options	2,140		542
Initial public offering costs paid			(2,802)
Proceeds from issuance of restricted stock			963
Borrowings on revolving credit facility			3,000
Repayments of revolving credit facility			(501)
Net cash provided by financing activities	2,140		1,202
Effect of exchange rate changes on cash and cash equivalents	40		68
NET DECREASE IN CASH AND CASH EQUIVALENTS	(39,557)		(3,385)
CASH AND CASH EQUIVALENTS - Beginning of period	96,025	[1]	16,410
CASH AND CASH EQUIVALENTS - End of period	56,468		13,025
NONCASH INVESTING AND FINANCING ACTIVITIES:
Vesting of restricted and early exercised stock options	$ 681		$ 708

[1] The Condensed Consolidated Balance Sheet as of December 31, 2011 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.