Income Taxes - Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Tax at federal statutory rate	34.00%	34.00%	34.00%
State tax, net of federal benefit		(0.10%)	0.80%
Foreign rate differential	(0.10%)	1.00%	56.60%
Research and development credit	0.90%	15.90%	(133.90%)
Warrants			67.70%
Withholding taxes	0.20%	0.30%	(10.50%)
Stock-based compensation	(2.90%)	(8.70%)	224.90%
Non-deductible intercompany bad debt			3.90%
FIN 48 interest and release	(0.10%)	1.80%	(219.40%)
Other	(0.10%)	(0.20%)	59.60%
Deemed dividend from foreign liquidation	(1.40%)
Valuation allowance	(30.20%)	(46.10%)	(1357.70%)
Effective tax rate	0.30%	(2.10%)	(1274.00%)