Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Additional Information (Details)

v3.20.1
Fair Value Measurements - Additional Information (Details)
$ / shares in Units, shares in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2020
USD ($)
installment
$ / shares
shares
Mar. 31, 2019
USD ($)
Dec. 31, 2019
shares
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Gain due to change in value of note payable $ (4,000) $ 0  
VenturEast | BioServe      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Number of shares associated with notes payable (in shares) | shares 3   3
Shares issued, price per share (usd per share) | $ / shares $ 4.20    
Number of payments | installment 2    
Settlement payment amount $ 50,000    
Gain due to change in value of note payable 4,000 0  
2016 Offering | Significant Unobservable Inputs (Level 3) | Fair Value Measurements, Recurring      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Gain (loss) on derivative due to change in stock price $ 127,000 $ 7,000