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	3,792	$ 0	3,792	0	0	0
Issuance of common stock under Equity Incentive Plans, shares		292
Issuance of common stock under Equity Incentive Plans, value	752	$ 0	752	0	0	0
Repurchase of common stock	(621)	0	0	0	0	(621)
Net loss	(72,995)	0	0	(72,995)	0	0
Unrealized gain (loss) on investments	555	$ 0	0	0	555	0
Balance, shares at Jun. 30, 2016		104,152
Balance, value at Jun. 30, 2016	217,333	$ 104	1,402,190	(1,181,929)	336	(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	4,634	$ 0	4,634	0	0	0
Issuance of common stock under Equity Incentive Plans, shares		461
Issuance of common stock under Equity Incentive Plans, value	5,427	$ 0	5,427	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	(69,950)	0	0	(69,950)	0	0
Unrealized gain (loss) on investments	(19)	$ 0	0	0	(19)	0
Balance, shares at Jun. 30, 2017		105,703
Balance, value at Jun. 30, 2017	$ 106,313	$ 105	$ 1,430,630	$ (1,322,304)	$ (214)	$ (1,904)