Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Warrant Modification (Details)

v3.20.1
Stockholders' Equity - Warrant Modification (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 12 Months Ended
Jun. 24, 2018
Dec. 31, 2019
Sep. 30, 2019
Jun. 30, 2019
Mar. 31, 2019
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Class of Stock [Line Items]                        
Warrant shares issued (in shares)   807,436               807,436    
Warrant expense                   $ 5,780 $ 0  
General and administrative expense   $ 5,856 $ 5,107 $ 4,335 $ 4,016 $ 6,352 $ 2,174 $ 3,913 $ 1,775 $ 19,314 14,214 $ 600
Accrued liabilities               600        
Modification of Interstate Batteries warrant #1                     1,002  
Additional Paid-in Capital                        
Class of Stock [Line Items]                        
Modification of Interstate Batteries warrant #1               $ 1,000     $ 1,002  
Warrant 1 | Interstate Battery System International, Inc.                        
Class of Stock [Line Items]                        
Warrant shares issued (in shares)   702,247               702,247    
Warrant exercise price (in dollars per share)   $ 7.12               $ 7.12    
Post-modification exercise price of warrants (dollars per share) 3.33                      
Warrant expense $ 1,000                      
Black-Scholes-Merton assumption, per share fair value (dollars per share) $ 3.26                      
Expected years until exercise 2 years                      
Volatility 80.20%                 65.70%    
Discount rate 2.56%                      
Dividend rate 0.00%                 0.00%