Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Narrative) (Details)

v3.23.1
Fair Value Measurements (Narrative) (Details)
 3 Months Ended 12 Months Ended
Jan. 27, 2023
USD ($)
$ / shares
shares
Dec. 16, 2022
USD ($)
Oct. 11, 2022
USD ($)
$ / shares
shares
Mar. 31, 2023
USD ($)
Mar. 31, 2022
USD ($)
Dec. 31, 2022
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Gain (loss) on common stock warrant liabilities       $ (6,678,000)    
Common stock, value       130,000   $ 110,000
Common stock warrant liabilities       9,459,000   $ 13,869,000
Proceeds from issuance of common stock for at-the-market offering, net       $ 447,000 $ 4,226,000  
Expected life of the options to convert            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Warrant liability, measurement input       4.7   5.0
Checkpoint Common Stock Warrants            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Fair value of warrants   $ 7,900,000        
Checkpoint Common Stock Warrants | Common Stock Warrant            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Gain (loss) on common stock warrant liabilities   (1,200,000)   $ 7,600,000    
Net proceeds   6,700,000        
Checkpoint Common Stock Warrants | 2022 Director Offering            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Sale of stock, net proceeds   $ 6,700,000        
Avenue            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Stock offering, number of shares issued | shares 448,000          
Shares issued | shares     3,636,365      
Number of common stock (in units)     1      
Number of warrants (in units)     1      
Warrants issued | shares     545,454      
Unit Price Per Share | $ / shares $ 1.55          
Proceeds from issuance of common stock for at-the-market offering, net     $ 10,300,000      
Avenue | Contingent Conditions are Met [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Net proceeds $ 2,800,000          
Stock offering, number of shares issued | shares 1,940,299          
Common stock warrant liabilities $ 2,200,000          
Number of shares called by warrants | shares 1          
Exercise price of warrants | $ / shares $ 0.125          
Unit Price Per Share | $ / shares 1.55          
Avenue | Pre funded warrants            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Exercise price of warrants | $ / shares 0.0001   $ 0.0001      
Unit Price Per Share | $ / shares $ 1.5499   $ 3.2999      
Avenue | Common Stock and Pre-funded Warrants            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Number of warrants (in units)     1      
Unit Price Per Share | $ / shares     $ 3.30      
Common Stock Warrant            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Common stock warrant liabilities       9,459,000   $ 13,869,000
Common Stock Warrant | Checkpoint Common Stock Warrants            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Gain (loss) on common stock warrant liabilities       (7,566,000)    
Common stock warrant liabilities       3,604,000   11,170,000
Common Stock Warrant | Avenue            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Issuance of Warrants       2,235,000   8,300,000
Gain (loss) on common stock warrant liabilities       878,000    
Common stock warrant liabilities       5,722,000   $ 2,609,000
Common Stock Warrant | Avenue | Pre funded warrants            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Number of shares called by warrants | shares 1,492,299          
Common Stock Warrant | Urica            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Gain (loss) on common stock warrant liabilities       10,000    
Placement Agent Warrants | Urica            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Issuance of Warrants       $ 33,000    
Placement Agent Warrants | Urica | Expected life of the options to convert            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Warrant liability, measurement input       1.2   1.5
Contingent Payment Warrants | Avenue | Expected life of the options to convert            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Warrant liability, measurement input       4.53   4.78
Contingent Payment Warrants | Urica            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Fair value of warrants       $ 100,000   $ 100,000