Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Gain (Loss)	Treasury Stock
Balance, shares at Dec. 31, 2015		103,860
Balance, value at Dec. 31, 2015	$ 285,850	$ 104	$ 1,397,646	$ (1,108,934)	$ (219)	$ (2,747)
Issuance of common stock to designees of Symphony Icon Holdings LLC, value	0
Stock-based compensation	5,722	$ 0	5,722	0	0	0
Issuance of common stock under Equity Incentive Plans, shares		463
Issuance of common stock under Equity Incentive Plans, value	2,943	$ 0	2,943	0	0	0
Repurchase of common stock	(621)	0	0	0	0	(621)
Net loss	(109,010)	0	0	(109,010)	0	0
Unrealized gain on investments	297	$ 0	0	0	297	0
Balance, shares at Sep. 30, 2016		104,323
Balance, value at Sep. 30, 2016	185,181	$ 104	1,406,311	(1,217,944)	78	(3,368)
Balance, shares at Dec. 31, 2016		104,582
Balance, value at Dec. 31, 2016	157,401	$ 105	1,411,222	(1,250,363)	(195)	(3,368)
Cumulative effect of change in accounting principle	0	$ 0	1,991	(1,991)	0	0
Issuance of common stock to designees of Symphony Icon Holdings LLC, shares		660
Issuance of common stock to designees of Symphony Icon Holdings LLC, value	10,499	$ 0	10,499	0	0	0
Stock-based compensation	7,214	$ 0	7,214	0	0	0
Issuance of common stock under Equity Incentive Plans, shares		468
Issuance of common stock under Equity Incentive Plans, value	5,481	$ 1	5,480	0	0	0
Issuance of treasury stock	0	0	(3,143)	0	0	(3,143)
Repurchase of common stock	(1,679)	0	0	0	0	(1,679)
Net loss	(100,672)	0	0	(100,672)	0	0
Unrealized gain on investments	132	$ 0	0	0	132	0
Balance, shares at Sep. 30, 2017		105,710
Balance, value at Sep. 30, 2017	$ 78,376	$ 106	$ 1,433,263	$ (1,353,026)	$ (63)	$ (1,904)