Stock-Based Compensation - Stock Options & RSUs (Details)	6 Months Ended
	Sep. 30, 2019 plan $ / shares shares
Stock-Based Compensation
Number of stock incentive plans | plan	2
Vested and expected to vest at the end of the period (in shares)	5,000,000
Stock options
Number of Shares
Options outstanding at the beginning of the period (in shares)	5,035,000
Exercised (in shares)	(33,000)
Forfeited (in shares)	(14,000)
Options outstanding at the end of the period (in shares)	4,988,000
Weighted Average Exercise Price Per Share
Options outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 3.70
Exercised (in dollars per share) | $ / shares	2.34
Forfeited (in dollars per share) | $ / shares	4.39
Options outstanding at the end of the period (in dollars per share) | $ / shares	$ 3.70
Restricted stock units
Weighted Average Exercise Price Per Share
Number of shares of common stock receivable upon vesting of each RSU	1
Number of Shares
RSUs outstanding at the beginning of the period (in shares)	112,000
Granted (in shares)	327,000
Vested (in shares)	(61,000)
Forfeited (in shares)	(2,000)
RSUs outstanding at the end of the period (in shares)	376,000
2016 Plan
Stock-Based Compensation
Authorized for future issuance under stock incentive plans (in shares)	2,700,000