Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock	Treasury Stock	Additional Paid-In Capital (Deficit)	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2010	$ (97,231)	$ 1	$ 0	$ 597	$ (97,802)	$ (27)
Beginning balance (in shares) at Dec. 31, 2010		10,586,000	0
Accretion of preferred stock	(5,208)			(2,259)	(2,949)
Conversion of preferred stock to common stock (in shares)		28,809,000
Conversion of preferred stock to common stock	132,775	3		132,772
Issuance of common stock for the exercise of warrants to purchase common stock (in shares)		898,000
Issuance of common stock for the exercise of warrants to purchase common stock	474			474
Issuance of common stock upon initial public offering, net of issuance costs (in shares)		7,500,000
Issuance of common stock upon initial public offering, net of issuance costs	86,853	1		86,852
Issuance of common stock to a non-profit organization (in shares)		20,000
Issuance of common stock to a non-profit organization	193			193
Issuance of common stock upon the exercise of options (in shares)		1,461,000
Issuance of common stock upon the exercise of options	1,017			1,017
Issuance of common stock warrants	2,500			2,500
Vesting of early exercised options	82			82
Tax withholding on net exercise of stock-based awards	(48)			(48)
Stock-based compensation	4,736			4,736
Net change in unrealized gains (losses) on investments	0
Net loss	(63,900)				(63,900)
Other comprehensive income (loss), net of tax	217					217
Ending balance at Dec. 31, 2011	62,460	5	0	226,916	(164,651)	190
Ending balance (in shares) at Dec. 31, 2011		49,274,000	0
Issuance of common stock for the exercise of warrants to purchase common stock (in shares)		130,000
Issuance of common stock for the exercise of warrants to purchase common stock	208			208
Issuance of common stock upon the exercise of options (in shares)		1,127,000
Issuance of common stock upon the exercise of options	2,490			2,490
Vesting of early exercised options	55			55
Vesting of restricted stock units (in shares)		112,000
Vesting of restricted stock units	0
Shares issued for Sonar Limited (in shares)		47,000
Shares issued for acquisition of Sonar Limited	335			335
Stock-based compensation	12,763			12,763
Net change in unrealized gains (losses) on investments	0
Net loss	(31,390)				(31,390)
Other comprehensive income (loss), net of tax	(273)					(273)
Ending balance at Dec. 31, 2012	46,648	5	0	242,767	(196,041)	(83)
Ending balance (in shares) at Dec. 31, 2012		50,690,000	0
Issuance of common stock upon the exercise of options (in shares)	1,566,000	1,566,000
Issuance of common stock upon the exercise of options	13,432			13,432
Vesting of early exercised options	28			28
Vesting of restricted stock units (in shares)		214,000
Vesting of restricted stock units	0
Tax withholding on net exercise of stock-based awards	(29)			(29)
Stock-based compensation	21,769			21,769
Net change in unrealized gains (losses) on investments	130					130
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	11,282			11,282
Net loss	(40,426)				(40,426)
Other comprehensive income (loss), net of tax	3					3
Ending balance at Dec. 31, 2013	$ 52,895	$ 5	$ 0	$ 289,307	$ (236,467)	$ 50
Ending balance (in shares) at Dec. 31, 2013		52,470,000	0