Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Shares (Details)

v3.20.1
Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Shares (Details) - shares
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities (in shares) 76,980,858 30,769,732
Warrant liability    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities (in shares) 44,722,222 0
Outstanding stock options    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities (in shares) 7,684,762 5,310,498
Outstanding restricted stock units    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities (in shares) 862,514 107,841
Warrants to purchase Series C-1 Preferred | Warrant liability    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities (in shares) 0 14,033
Warrants to purchase common stock associated with Solar loan agreement | Warrant liability    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities (in shares) 122,435 122,435
Warrants to purchase common stock associated with June 2016 Public Offering | Warrant liability    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities (in shares) 4,218,750 4,218,750
March 2018 Public Offering Series 2 [Member] | Warrant liability    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities (in shares) 7,988,175 7,988,175
Common stock associated with 6% convertible senior notes    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities (in shares) 11,382,000 13,008,000