Annual report pursuant to Section 13 and 15(d)

Equity (Details)

v3.21.1
Equity (Details) - USD ($)
1 Months Ended 12 Months Ended
Mar. 14, 2017
Aug. 31, 2020
Jul. 19, 2020
Jun. 19, 2020
Apr. 24, 2020
Apr. 30, 2019
Oct. 31, 2018
Mar. 31, 2018
Sep. 30, 2013
Dec. 31, 2020
Dec. 31, 2019
Nov. 18, 2020
Apr. 30, 2020
Jun. 30, 2019
Dec. 31, 2013
Equity (Details) [Line Items]                              
Description of shares         the Company issued and sold 4.3 million shares of common stock and 2.8 million pre-funded warrants to purchase shares of common stock. The price to the public in this offering for each share of common stock was $4.50 and for each pre-funded warrant was $4.497. Each pre-funded warrant had an exercise price of $0.003 per share and was exercisable immediately upon issuance. Gross proceeds from this offering were $31.6 million, before deducting underwriting discounts and commissions and other offering expenses payable by the Company. Net proceeds from this offering were $29.1 million.                    
Sale of common stock           1,400,000                  
Exercise price of warrants (in Dollars per share)           $ 15.00             $ 26.40 $ 15.61515  
Warrant to purchase of common stock 1,907         1,400,000                  
Gross proceeds (in Dollars)           $ 16,500,000       $ 22,600,000          
Net proceeds (in Dollars)           $ 15,100,000                  
Equity description   the Company entered into the Capital on Demand™ Sales Agreement with JonesTrading Institutional Services LLC (“JonesTrading”), pursuant to which the Company may sell, from time to time, through or to JonesTrading, up to an aggregate of $200 million of its common stock. Shares of common stock are offered pursuant to the Company’s shelf registration statement on Form S-3 filed with the SEC on August 7, 2020.                          
Sale of common stock, shares                   2,100,000 93,000        
Net proceeds on sale of common stock (in Dollars)                   $ 21,700,000 $ 700,000        
Offering price (in Dollars per share)           $ 11.55                  
Discount rate           2.35%                  
Expected term           5 years                  
Expected volatility           78.00%                  
Expected dividends           0.00%                  
Sale of stock, description               the Company sold an aggregate of 1.0 million units consisting of an aggregate of 1.0 million shares of common stock, 0.3 million series A warrants and 0.8 million series B warrants, with each series A warrant exercisable for one share of common stock at an exercise price of $18.00 per share and each series B warrant exercisable for one share of common stock at an exercise price of $21.00 per share. During the year ended December 31, 2019, holders of March 2018 series A warrants exercised 84 thousand shares, resulting in the Company receiving $1.5 million. The remaining March 2018 series A warrants expired in March 2019. The March 2018 Series B warrants expired in September 2020.              
Deemed dividend (in Dollars)                   1,000 1        
Stock-based compensation expense (in Dollars)                   $ 13,000 $ 8,000        
Equity Option [Member]                              
Equity (Details) [Line Items]                              
Stock option granted                   458,000 195,000        
Option exercise price minimum (in Dollars per share)                   $ 6.63 $ 6.44        
Option exercise price maximum (in Dollars per share)                   $ 12.41 $ 17.40        
Stock options, term                   10 years 10 years        
Aggregated fair value (in Dollars)                   $ 3,200,000 $ 1,100,000        
Stock option, description                   Variables used in the Black-Scholes option-pricing model include: (1) discount rate range from 0.34% to 0.56% (2) expected life of 6 years, (3) expected volatility range from 83.6% to 85.5%, and (4) zero expected dividends. Variables used in the Black-Scholes option-pricing model include: (1) discount rate range from 1.38% to 2.6% (2) expected life of 6 years, (3) expected volatility range from 78.5% to 81.8%, and (4) zero expected dividends.        
Number of options, shares cancelled                   23,000 56,000        
Unvested options (in Dollars)                   $ 4,000,000          
weighted average Term                   3 years 109 days          
Total option expense (in Dollars)                   $ 1,200,000 $ 1,200,000        
Minimum [Member]                              
Equity (Details) [Line Items]                              
Exercise price of warrants (in Dollars per share)           $ 26.40                  
Minimum [Member] | Equity Option [Member]                              
Equity (Details) [Line Items]                              
Vesting period                   4 years 4 years        
Maximum [Member]                              
Equity (Details) [Line Items]                              
Exercise price of warrants (in Dollars per share)           $ 37.50                  
Maximum [Member] | Equity Option [Member]                              
Equity (Details) [Line Items]                              
Vesting period                   4 years 73 days 4 years 73 days        
Lincoln Park Capital Fund, LLC [Member]                              
Equity (Details) [Line Items]                              
Sale of common stock, shares                   27,000 13,000        
Aggregate value of common stock, shares over life of agreement (in Dollars)             $ 32,500,000                
Received amount (in Dollars)                   $ 200,000 $ 100,000        
2019 Amended and Restated Stock Plan [Member]                              
Equity (Details) [Line Items]                              
Number of shares authorized                     333,333        
Total number of shares of common stock available for grant                       3,083,333      
Plan expiration date                     Oct. 18, 2029        
2013 Amended and Restated Stock Plan [Member]                              
Equity (Details) [Line Items]                              
Number of shares authorized                 91,666            
Total number of shares of common stock available for grant                 758,333            
Plan expiration date                 Sep. 09, 2023            
2013 Equity Incentive Plan [Member]                              
Equity (Details) [Line Items]                              
Number of shares authorized                 15,000            
Total number of shares of common stock available for grant                             33,333
Plan expiration date                 Sep. 09, 2023            
Warrant [Member]                              
Equity (Details) [Line Items]                              
Sale of common stock       1,900,000   1,400,000       2,800,000          
Exercise price of warrants (in Dollars per share)       $ 0.003   $ 15.00       $ 0.003          
Warrant to purchase of common stock       700,000   1,400,000       2,800,000          
Share price (in Dollars per share)       $ 9.75                      
Pre-funded warrant per share (in Dollars per share)       $ 9.747                      
Gross proceeds (in Dollars)     $ 25,000,000                        
Net proceeds (in Dollars)     $ 23,000,000                        
Offering price (in Dollars per share)           $ 11.55                  
Aggregated fair value (in Dollars)           $ 5,300,000                  
Warrant term           5 years                  
Sale of stock, description               the Company sold an aggregate of 1.0 million units consisting of an aggregate of 1.0 million shares of common stock, 0.3 million series A warrants and 0.8 million series B warrants, with each series A warrant exercisable for one share of common stock at an exercise price of $18.00 per share and each series B warrant exercisable for one share of common stock at an exercise price of $21.00 per share. During the year ended December 31, 2019, holders of March 2018 series A warrants exercised 84 thousand shares, resulting in the Company receiving $1.5 million. The remaining March 2018 series A warrants expired in March 2019. The March 2018 Series B warrants expired in September 2020.              
Pre-funded Warrants [Member]                              
Equity (Details) [Line Items]                              
Sale of common stock                   700,000          
Exercise price of warrants (in Dollars per share)                   $ 0.003          
Warrant to purchase of common stock                   700,000          
Share price (in Dollars per share)                   $ 0.003          
Common Stock [Member]                              
Equity (Details) [Line Items]                              
Sale of common stock, shares                   300,000          
Net proceeds on sale of common stock (in Dollars)                   $ 2,500,000