Condensed Consolidated Statements of Comprehensive Loss (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net loss	$ (6,375)	$ (9,623)
Other comprehensive income:
Unrealized gain on marketable securities, net of tax of $248 and $123 for the three months ended March 31, 2014 and 2013, respectively	402	192
Other comprehensive income	402	192
Total comprehensive loss	$ (5,973)	$ (9,431)