General form of registration statement for all companies including face-amount certificate companies

Stockholders' deficit - Equity transactions (Q1) (Details)

v3.21.1
Stockholders' deficit - Equity transactions (Q1) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Jan. 22, 2021
Dec. 31, 2020
Dec. 31, 2019
Mar. 31, 2021
Dec. 12, 2018
Class of Stock [Line Items]          
Proceeds from shares and warrants issued pursuant to private placement, net   $ 18,053 $ 15,826    
Common stock, par value (in dollars per share)   $ 0.001 $ 0.001 $ 0.001  
Number of warrants included in each unit (in shares)         1
Number of shares issuable per warrant (in shares)         0.50
PIPE transaction          
Class of Stock [Line Items]          
Gross consideration $ 4,100        
Purchase price (in dollars per share) $ 1.25        
Number of shares of stock included in each unit (in shares) 1        
Common stock, par value (in dollars per share) $ 0.001        
Number of warrants included in each unit (in shares) 1        
Number of shares issuable per warrant (in shares) 1        
PIPE transaction | Officers and directors          
Class of Stock [Line Items]          
Proceeds from shares and warrants issued pursuant to private placement, net $ 1,600