Organization and Summary of Significant Accounting Policies - Fair Value Warrant Liabilities Recurring Basis (Details) - Warrant - Fair Value, Measurements, Recurring $ in Thousands	Dec. 31, 2017 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on a recurring basis	$ 694
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on a recurring basis	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on a recurring basis	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on a recurring basis	$ 694