Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (16,013)	$ 398	$ (19,612)	$ 2,148
Unrealized gain (loss) on marketable securities, net of taxes of $0	21	(11)	49	(20)
Total comprehensive income (loss)	$ (15,992)	$ 387	$ (19,563)	$ 2,128