Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Total Stockholders Equity [Member]
Beginning Balance at Dec. 31, 2012		$ 123	$ 60	$ 463,710	$ 273	$ (175,485)	$ 0	$ 288,681
Beginning Balance, Shares at Dec. 31, 2012		20	60,026,675				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ (62,134)					(62,134)		(62,134)
Other comprehensive Income (loss), net	$ 621				621			621
Issuance of common stock to 401(k) plan				860				860
Issuance of common stock to 401(k) plan, Shares			99,359
Issuance of common stock for ESPP				495				495
Issuance of common stock for ESPP, Shares			74,925
Issuance of common stock upon exercise of stock options			$ 1	3,576				3,577
Issuance of common stock upon exercise of stock options, Shares	825,884		825,884
Share-based compensation expense and common stock issued (net of forfeitures)				11,193				11,193
Share-based compensation expense and common stock issued (net of forfeitures), Shares			471,875
Repurchase of shares to satisfy employee tax withholding				(1,509)				(1,509)
Repurchase of shares to satisfy employee tax withholding, Shares			(159,545)
Purchase of treasury stock							$ (1,651)	(1,651)
Purchase of treasury stock, Shares							235,000,000
Retirement of treasury stock	$ (1,652)			(1,651)			$ 1,651	0
Retirement of treasury stock, Shares			(235,000)				(235,000,000)
Issuance of common stock for Talon acquisition			$ 3	26,307				26,310
Issuance of common stock for Talon acquisition, Shares			3,000,000
Issuance of 2018 Convertible Notes				14,443				14,443
Ending Balance at Dec. 31, 2013		$ 123	$ 64	518,144	894	(237,619)	$ 0	281,606
Ending Balance, Shares at Dec. 31, 2013		20	64,104,173				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(45,719)					(45,719)		(45,719)
Other comprehensive Income (loss), net	$ (1,744)				(1,744)			(1,744)
Issuance of common stock to 401(k) plan				1,028				1,028
Issuance of common stock to 401(k) plan, Shares			133,734
Issuance of common stock for ESPP				639				639
Issuance of common stock for ESPP, Shares			99,551
Issuance of common stock upon exercise of stock options			$ 1	1,905				1,906
Issuance of common stock upon exercise of stock options, Shares	485,260		485,260
Share-based compensation expense and common stock issued (net of forfeitures)				10,781				10,781
Share-based compensation expense and common stock issued (net of forfeitures), Shares			396,083
Repurchase of shares to satisfy employee tax withholding				(1,733)				(1,733)
Repurchase of shares to satisfy employee tax withholding, Shares			(249,102)
Retirement of treasury stock	$ 0
Issuance of common stock to TopoTarget for milestone achievement			$ 1	7,789				7,790
Issuance of common stock to TopoTarget for milestone achievement, Shares			1,000,000
Ending Balance at Dec. 31, 2014	$ 254,554	$ 123	$ 66	538,553	(850)	(283,338)	$ 0	254,554
Ending Balance, Shares at Dec. 31, 2014	65,969,699	20	65,969,699				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ (50,785)					(50,785)		(50,785)
Other comprehensive Income (loss), net	(4,469)				(4,469)			(4,469)
Issuance of common stock to 401(k) plan				1,124				1,124
Issuance of common stock to 401(k) plan, Shares			179,865
Issuance of common stock for ESPP				627				627
Issuance of common stock for ESPP, Shares			114,578
Issuance of common stock upon exercise of stock options			$ 0	1,482				1,482
Warrant modification	$ 568			568
Issuance of common stock upon exercise of stock options, Shares	456,082		456,082
Share-based compensation expense and common stock issued (net of forfeitures)	$ 2			10,392				10,394
Share-based compensation expense and common stock issued (net of forfeitures), Shares			1,613,553
Repurchase of shares to satisfy employee tax withholding				(638)				(638)
Repurchase of shares to satisfy employee tax withholding, Shares			(104,842)
Retirement of treasury stock	0
Ending Balance at Dec. 31, 2015	$ 212,857	$ 123	$ 68	$ 552,108	$ (5,319)	$ (334,123)	$ 0	$ 212,857
Ending Balance, Shares at Dec. 31, 2015	68,228,935	20	68,228,935				0