Stock Based Compensation - Assumptions to determine grant-date fair value of stock options (Details) |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Stock-Based Compensation | ||||
| Risk-free interest rate | 1.68% | 2.83% | 2.17% | 2.83% |
| Expected term (in years) | 6 years 1 month 6 days | 6 years 1 month 6 days | 6 years | 6 years 1 month 6 days |
| Expected volatility | 69.70% | 63.30% | 71.00% | 61.70% |
| Expected dividend yield | 0.00% | 0.00% | 0.00% | 0.00% |