Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt and Other Financings - Silicon Valley Bank Loan Agreement (Details)

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Long-Term Debt and Other Financings - Silicon Valley Bank Loan Agreement (Details) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended 12 Months Ended
Mar. 04, 2019
May 07, 2018
Sep. 30, 2018
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2019
Dec. 31, 2020
Long-term debt              
Debt amount       $ 18,855      
Current portion of long-term debt       7,201     $ 8,088
Long-term debt       $ 11,654     $ 12,764
Common stock warrant, Exercise price $23.69 per share, Issued May 2018              
Long-term debt              
Exercise price of per share (in dollars per share)       $ 23.69     $ 23.69
Common stock warrant, Exercise price $14.71 per share, Issued March 2019              
Long-term debt              
Exercise price of per share (in dollars per share)       $ 14.71     $ 14.71
Silicon Valley Bank Loans              
Long-term debt              
Maximum borrowing capacity under loan agreement   $ 20,000          
Period of monthly payments of principal and interest   24 months          
Maximum period following loan amortization date for which loan will mature   23 months          
Maximum period prior to loan maturity date of Novartis loan for which loan will mature   30 days          
Amount of loan that may be reborrowed after repayment   $ 0          
Final payment fee (as a percent)   8.50%          
Additional interest rate in the event of default (as a percent)   4.00%          
Debt issuance costs   $ 200          
Non-cash interest expense resulting from amortization of discount and accretion of final payment       $ 100 $ 200    
Debt amount       9,800     $ 11,800
Current portion of long-term debt       7,200     8,100
Long-term debt       $ 2,600     $ 3,700
Silicon Valley Bank Loans | Minimum              
Long-term debt              
Interest rate (as a percent)   4.75%          
Silicon Valley Bank Loans | Common stock warrant, Exercise price $23.69 per share, Issued May 2018              
Long-term debt              
Aggregate number of shares of common stock called by warrants   6,332          
Exercise price of per share (in dollars per share)   $ 23.69          
Exercisable period of warrants   10 years          
Fair value of warrant   $ 100          
Silicon Valley Bank Loans | Common stock warrant, Exercise price $14.71 per share, Issued March 2019              
Long-term debt              
Aggregate number of shares of common stock called by warrants 4,845            
Exercise price of per share (in dollars per share) $ 14.71            
Exercisable period of warrants 10 years            
Fair value of warrant $ 100            
Silicon Valley Bank Loans | Prime Rate              
Long-term debt              
Basis spread on variable rate   0.25%          
Silicon Valley Bank Loans | Following first anniversary              
Long-term debt              
Prepayment fee (as a percent)   2.00%          
Silicon Valley Bank Loans | Following second anniversary              
Long-term debt              
Prepayment fee (as a percent)   1.00%          
Silicon Valley Bank, First Term Loan              
Long-term debt              
Proceeds from issuance of long-term debt     $ 7,500        
Unamortized discount     $ 300        
Silicon Valley Bank, Second Term Loan              
Long-term debt              
Proceeds from issuance of long-term debt           $ 9,500  
Unamortized discount           $ 45