Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net loss	$ (7,891)	$ (3,102)	$ (21,288)	$ (8,623)
Other comprehensive loss, net:
Change in unrealized (loss) gain on investments, net	(31)	89	(55)	(3)
Comprehensive loss	$ (7,922)	$ (3,013)	$ (21,343)	$ (8,626)