Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 5,394	$ (4,562)	$ (5,528)	$ (19,416)
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities, net of tax expense of $263 and $160 for the three months ended September 30, 2015 and 2014, respectively, and tax benefit of $200 and $89 for the nine months ended September 30, 2015 and 2014, respectively.	(449)	(261)	343	145
Other comprehensive income (loss)	(449)	(261)	343	145
Total comprehensive income (loss)	$ 4,945	$ (4,823)	$ (5,185)	$ (19,271)