Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss) including noncontrolling interests in operating subsidiaries	$ (54,799)	$ (157,478)	$ (66,662)
Other comprehensive income (loss):
Unrealized loss on short-term investments	40	(356)	(1,488)
Unrealized gain on foreign currency translation	77	(123)	(128)
Add: reclassification adjustment for losses included in net income	22	617	2,210
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	(54,660)	(157,340)	(66,068)
Net (income) loss attributable to noncontrolling interests in operating subsidiaries	(732)	2,558	(633)
Comprehensive income	$ (53,928)	$ (159,898)	$ (65,435)