CONDENSED CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEICIT) - USD ($)
$ in Thousands
Convertible preferred stock
Common stock
ATM sales
Common stock
Follow-on public offering
Common stock
Initial public offering
Common stock
Additional paid-in capital
ATM sales
Additional paid-in capital
Follow-on public offering
Additional paid-in capital
Initial public offering
Additional paid-in capital
Accumulated deficit
Accumulated other comprehensive loss
ATM sales
Follow-on public offering
Initial public offering
Total
Balance at Mar. 31, 2018 $ 86,361       $ 5       $ 1,097 $ (28,932) $ (238)       $ (28,068)
Balance (in shares) at Mar. 31, 2018 1,925,968       5,007,485                    
Increase (decrease) in Stockholders' Equity                              
Foreign currency translation adjustment                     (847)       (847)
Unrealized gain (loss) on short-term investments                     35       35
Stock-based compensation expense                 225           225
Net loss                   (10,044)         (10,044)
Balance at Jun. 30, 2018 $ 86,361       $ 5       1,322 (38,976) (1,050)       (38,699)
Balance (in shares) at Jun. 30, 2018 1,925,968       5,007,485                    
Balance at Mar. 31, 2018 $ 86,361       $ 5       1,097 (28,932) (238)       (28,068)
Balance (in shares) at Mar. 31, 2018 1,925,968       5,007,485                    
Increase (decrease) in Stockholders' Equity                              
Foreign currency translation adjustment                             (1,088)
Unrealized gain (loss) on short-term investments                             (54)
Conversion of convertible preferred stock into common stock upon closing of initial public offering                             7,094
Conversion of convertible preferred stock warrants into common stock warrants                             86,361
Net loss                             (24,178)
Balance at Dec. 31, 2018         $ 32       197,697 (53,110) (1,380)       143,239
Balance (in shares) at Dec. 31, 2018         31,640,672                    
Balance at Jun. 30, 2018 $ 86,361       $ 5       1,322 (38,976) (1,050)       (38,699)
Balance (in shares) at Jun. 30, 2018 1,925,968       5,007,485                    
Increase (decrease) in Stockholders' Equity                              
Foreign currency translation adjustment                     (139)       (139)
Unrealized gain (loss) on short-term investments                     (34)       (34)
Exercise of stock options         $ 1       11           12
Exercise of stock options (in shares)         7,149                    
Conversion of convertible preferred stock into common stock upon closing of initial public offering $ (86,361)       $ 19       86,342           86,361
Conversion of convertible preferred stock into common stock upon closing of initial public offering (in shares) (1,925,968)       19,157,360                    
Conversion of convertible preferred stock warrants into common stock warrants                 7,094           7,094
Repurchase of class A common stock upon closing of initial public offering (in shares)         (26,258)                    
Issuance of common shares upon closing of follow-on public offering, net of issuance costs and underwriter fees       $ 7       $ 101,177           $ 101,184  
Issuance of common shares upon closing of follow-on public offering, net of issuance costs and underwriter fees (in shares)       7,407,936                      
Stock-based compensation expense                 718           718
Net loss                   (6,461)         (6,461)
Balance at Sep. 30, 2018         $ 32       196,664 (45,437) (1,223)       150,036
Balance (in shares) at Sep. 30, 2018         31,553,672                    
Increase (decrease) in Stockholders' Equity                              
Foreign currency translation adjustment                     (102)       (102)
Unrealized gain (loss) on short-term investments                     (55)       (55)
Exercise of stock options                 153           153
Exercise of stock options (in shares)         87,000                    
Stock-based compensation expense                 880           880
Net loss                   (7,673)         (7,673)
Balance at Dec. 31, 2018         $ 32       197,697 (53,110) (1,380)       143,239
Balance (in shares) at Dec. 31, 2018         31,640,672                    
Balance at Mar. 31, 2019         $ 32       198,645 (59,766) (1,055)       137,856
Balance (in shares) at Mar. 31, 2019         31,656,950                    
Increase (decrease) in Stockholders' Equity                              
Foreign currency translation adjustment                     (182)       (182)
Unrealized gain (loss) on short-term investments                     65       65
Exercise of stock options                 18           18
Exercise of stock options (in shares)         6,751                    
Impact of adoption of ASC 842                   93         93
Stock-based compensation expense                 1,810           1,810
Net loss                   (9,508)         (9,508)
Balance at Jun. 30, 2019         $ 32       200,473 (69,181) (1,172)       130,152
Balance (in shares) at Jun. 30, 2019         31,663,701                    
Balance at Mar. 31, 2019         $ 32       198,645 (59,766) (1,055)       137,856
Balance (in shares) at Mar. 31, 2019         31,656,950                    
Increase (decrease) in Stockholders' Equity                              
Foreign currency translation adjustment                             $ 8
Exercise of stock options (in shares)                             184,580
Issuance of common shares upon closing of follow-on public offering, net of issuance costs and underwriter fees (in shares)                       287,559      
Net loss                             $ (36,836)
Balance at Dec. 31, 2019         $ 37       295,084 (96,509) (1,047)       197,565
Balance (in shares) at Dec. 31, 2019         36,645,650                    
Balance at Jun. 30, 2019         $ 32       200,473 (69,181) (1,172)       130,152
Balance (in shares) at Jun. 30, 2019         31,663,701                    
Increase (decrease) in Stockholders' Equity                              
Foreign currency translation adjustment                     (218)       (218)
Unrealized gain (loss) on short-term investments                     (40)       (40)
Exercise of stock options                 105           105
Exercise of stock options (in shares)         55,645                    
Stock-based compensation expense                 1,781           1,781
Net loss                   (11,139)         (11,139)
Balance at Sep. 30, 2019         $ 32       202,359 (80,320) (1,430)       120,641
Balance (in shares) at Sep. 30, 2019         31,719,346                    
Increase (decrease) in Stockholders' Equity                              
Foreign currency translation adjustment                     408       408
Unrealized gain (loss) on short-term investments                     (25)       (25)
Exercise of stock options                 357           357
Exercise of stock options (in shares)         122,184                    
Conversion of convertible preferred stock warrants into common stock warrants                 28,145           28,145
Issuance of common shares upon closing of follow-on public offering, net of issuance costs and underwriter fees     $ 5     $ 4,431 $ 57,448         $ 4,431 $ 57,453    
Issuance of common shares upon closing of follow-on public offering, net of issuance costs and underwriter fees (in shares)   287,559 4,516,561                        
Stock-based compensation expense                 2,344           2,344
Net loss                   (16,189)         (16,189)
Balance at Dec. 31, 2019         $ 37       $ 295,084 $ (96,509) $ (1,047)       $ 197,565
Balance (in shares) at Dec. 31, 2019         36,645,650