Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Evaluation of Ability to Maintain Current Level of Operations (Details)

v3.19.2
Summary of Significant Accounting Policies - Evaluation of Ability to Maintain Current Level of Operations (Details)
3 Months Ended 12 Months Ended
Feb. 04, 2019
USD ($)
Jun. 02, 2017
USD ($)
Mar. 31, 2019
USD ($)
agreement
Mar. 31, 2019
USD ($)
Mar. 31, 2018
USD ($)
Mar. 31, 2017
USD ($)
Net loss       $ 16,659,000 $ 10,026,000  
Increase in warranty provision       700,000    
Higher FPP scheduled and unscheduled maintenance costs       3,000,000    
Cash used in operating activities       17,703,000 8,641,000  
Cash, cash equivalents and restricted cash     $ 29,727,000 29,727,000 19,408,000 $ 19,705,000
Outstanding borrowings         8,527,000  
Bridge Bank            
Term of credit agreements   2 years        
Note Purchase Agreements | Goldman Sachs            
Maximum borrowing capacity under facility $ 30,000,000          
Credit Facility            
Outstanding borrowings     30,000,000 30,000,000    
Credit Facility | Bridge Bank            
Outstanding borrowings     $ 0 0 $ 8,500,000  
Maximum borrowing capacity under facility   $ 12,000,000        
Credit Facility | Bridge Bank Credit Agreements | Bridge Bank            
Number of credit and security agreements | agreement     2      
Credit Facility | Bridge Bank Credit Agreements | Wells Fargo            
Maximum borrowing capacity under facility     $ 15,000,000 15,000,000    
Note Payable | Goldman Sachs            
Term of credit agreements 3 years          
Doubt about Company’s ability to meet obligations for next 12 months            
Net loss       16,700,000    
Cash used in operating activities       17,700,000    
Cash, cash equivalents and restricted cash     $ 29,700,000 $ 29,700,000    
Through the first anniversary date of February 4, 2020 | Note Payable | Note Purchase Agreements | Goldman Sachs            
Cash, cash equivalents and restricted cash $ 12,000,000          
Thereafter | Note Payable | Note Purchase Agreements | Goldman Sachs            
Cash, cash equivalents and restricted cash $ 9,000,000