Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Summary of Reconciliation of Beginning and Ending Balances for Liabilities Measured at Fair Value on Recurring Basis (Details)

v3.19.1
Fair Value Measurements - Summary of Reconciliation of Beginning and Ending Balances for Liabilities Measured at Fair Value on Recurring Basis (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2018
USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]  
Beginning balance $ 3,872
Gain adjustment to fair value (11,866)
Ending balance 986
Series 1 | Warrant liability  
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]  
March 2018 Public Offering 3,480
Series 2 | Warrant liability  
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]  
March 2018 Public Offering $ 5,500