XML 61 R50.htm IDEA: XBRL DOCUMENT v3.19.2
Stock-Based Compensation - Black-Scholes Option-Pricing Model (Details) - Employee Stock Purchase Plan
Mar. 15, 2019
$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Grant price (in dollars per share) $ 2.49
Expected term 3 months
Expected volatility 62.97%
Risk-free interest rate 2.21%
Expected dividend yield 0.00%