Stock-Based Compensation (Details) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
	May 08, 2019	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($) shares	Sep. 30, 2020 USD ($) installment $ / shares shares	Sep. 30, 2019 USD ($) $ / shares shares	Apr. 30, 2020 shares	Mar. 31, 2019 shares
Stock-Based Compensation
Number of shares available for future issuance (in shares)							8,400
Number of options outstanding, before stock split (in shares)							15,400
Number of options outstanding (in shares)							1,900
Reverse share split ratio	0.125
Employees | RSL
Stock-Based Compensation
Share-based compensation expense | $		$ 9	$ (200)	$ 34	$ (100)
Restricted Stock Units (RSUs)
Stock-Based Compensation
RSUs outstanding (in shares)		900	300	900	300
RSUs granted (in shares)				1,000	300
Aggregate grant date fair value of RSUs | $				$ 3,400	$ 2,600
Number of equal annual vesting installment | installment				3
Restricted Stock Units (RSUs) | Tranche One
Stock-Based Compensation
RSUs vesting (as a percent)				50.00%
Restricted Stock Units (RSUs) | Tranche Two
Stock-Based Compensation
RSUs vesting (as a percent)				50.00%
Stock Options
Stock-Based Compensation
Number of options granted (in shares)					400
Exercise price of options granted (in USD per share) | $ / shares					$ 8.07
Estimated grant date fair value of options granted | $					$ 1,200
Total unrecognized compensation expense, stock options | $		$ 7,300		$ 7,300
Remaining weighted-average service period				2 years 5 months 8 days
Stock Options | Grants to Directors and Employees
Stock-Based Compensation
Share-based compensation expense | $		$ 1,100	$ 1,100	$ 2,700	$ 3,100
Time-Based Stock Options
Stock-Based Compensation
Vesting period				4 years
RSUs vesting (as a percent)				25.00%
Number of installments | installment				12
Market-Based Performance Stock Options
Stock-Based Compensation
Number of options outstanding (in shares)		400		400
Weighted average exercise price of options outstanding (in dollars per share) | $ / shares		$ 9.01		$ 9.01
Number of options granted (in shares)				0
Number of options vested (in shares)				19
Exercise price of options vested (in USD per share) | $ / shares				$ 11.68
2015 Equity Incentive Plan
Stock-Based Compensation
Shares authorized for issuance before split (in shares)							24,800
Number of shares reserved for grant (in shares)						5,600	3,100
Number of shares available for future grant (in shares)		2,100		2,100			1,000
2015 Equity Incentive Plan | Stock Options
Stock-Based Compensation
Number of options outstanding (in shares)		2,200	2,700	2,200	2,700
Weighted average exercise price of options outstanding (in dollars per share) | $ / shares		$ 12.30		$ 12.30
Number of options granted (in shares)				400	1,500
Exercise price of options granted (in USD per share) | $ / shares				$ 3.45	$ 8.15
Estimated grant date fair value of options granted | $				$ 1,100	$ 7,600