Annual report pursuant to Section 13 and 15(d)

Related-Party Transactions (Details)

v3.20.4
Related-Party Transactions (Details)
12 Months Ended
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
milestone
Dec. 31, 2017
USD ($)
Dec. 31, 2018
USD ($)
Sep. 20, 2013
USD ($)
Other Liabilities          
Related Party Transaction [Line Items]          
Due to related parties $ 6,000,000.0 $ 6,000,000.0   $ 600,000  
Settlement Agreement Payments | Affiliated Shareholder | ILJIN          
Related Party Transaction [Line Items]          
Settlement agreement terms         $ 10,000,000.0
Due to related parties 6,000,000.0 $ 7,800,000     $ 10,000,000.0
Number of milestone payments | milestone   2      
Milestone Payment | Affiliated Shareholder | ILJIN          
Related Party Transaction [Line Items]          
Payments to related party   $ 100,000 $ 2,200,000    
Discontinued DES Program | Affiliated Shareholder | ILJIN          
Related Party Transaction [Line Items]          
Due to related parties 1,800,000        
Legal Fees | Management          
Related Party Transaction [Line Items]          
Expenses from related party $ 392,000 $ 473,000