Share-Based Compensation (Summary of Stock Option Activity) (Details)	9 Months Ended
	Dec. 31, 2019 shares
Number of Options
Beginning balance (in shares)	5,396,465
Granted (in shares)	2,768,700
Exercised (in shares)	(80,548)
Forfeited (in shares)	(340,360)
Ending balance (in shares)	7,744,257
Options vested and expected to vest (in shares)	7,744,257
Vested executive options subject to one-year exercise restriction period (in shares)	735,428
Options exercisable (in shares)	2,857,183