XML 23 R22.htm IDEA: XBRL DOCUMENT v3.20.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - STOCK BASED COMPENSATION (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Stock-Based Compensation Expense    
Stock-based compensation expense included in operating expenses $ 1,568 $ 1,426
Research and development    
Stock-Based Compensation Expense    
Stock-based compensation expense included in operating expenses 501 240
General and administrative    
Stock-Based Compensation Expense    
Stock-based compensation expense included in operating expenses $ 1,067 $ 1,186