Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (62,879)	$ (77,830)
Other comprehensive income (loss):
Unrealized gain on investments, net of taxes	5	10
Unrealized loss on currency translation	(2)
Other comprehensive income	3	10
Comprehensive loss	$ (62,876)	$ (77,820)