Convertible Notes - Convertible Promissory Notes Outstanding (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Debt Instrument [Line Items]
Debt discount	$ (18,038)	$ (18,088)
Warrants Issued With September 2016 Convertible Notes
Debt Instrument [Line Items]
Debt discount	(9,617)	(9,643)	$ (9,600)
Compounded Bifurcated Derivatives
Debt Instrument [Line Items]
Debt discount	(1,269)	(1,273)	(1,300)
Beneficial Conversion Feature
Debt Instrument [Line Items]
Debt discount	(7,152)	(7,172)	(7,200)
Convertible Debt
Debt Instrument [Line Items]
Convertible promissory notes	18,038	18,088
Debt discount			$ (18,100)
Convertible promissory notes, net	$ 0	$ 0