Organization and Summary of Significant Accounting Policies - Fair Value Hierarchy of Warrant Liabilities (Details) - Fair Value, Measurements, Recurring - Warrants - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liabilities measured at fair value on a recurring basis	$ 636	$ 846
Quoted Market Prices for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liabilities measured at fair value on a recurring basis	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liabilities measured at fair value on a recurring basis	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liabilities measured at fair value on a recurring basis	$ 636	$ 846