Consolidated Statement of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Balance at Mar. 31, 2017	$ 305,043	$ 625	$ 228,549	$ 76,227	$ (358)
Balance, Shares at Mar. 31, 2017		62,455
Common stock issued under stock plans, net of shares withheld for taxes	3,833	$ 15	3,818
Common stock issued under stock plans, net of shares withheld for taxes, Shares		1,540
Stock-based compensation	12,196		12,196
Cumulative effect adjustment related to the adoption of ASU 2016-09	(40)		(101)	61
Other comprehensive income:
Translation adjustments	(42)				(42)
Net income	2,420			2,420
Balance at Mar. 31, 2018	323,410	$ 640	244,462	78,708	(400)
Balance, Shares at Mar. 31, 2018		63,995
Common stock issued under stock plans, net of shares withheld for taxes	4,352	$ 8	4,344
Common stock issued under stock plans, net of shares withheld for taxes, Shares		843
Stock-based compensation	16,102		16,102
Cumulative effect adjustment related to the adoption of ASU 2016-09	8,419			8,419
Other comprehensive income:
Translation adjustments	(831)				(831)
Net income	24,494			24,494
Balance at Mar. 31, 2019	375,946	$ 648	264,908	111,621	(1,231)
Balance, Shares at Mar. 31, 2019		64,838
Common stock issued under stock plans, net of shares withheld for taxes	(1,732)	$ 13	(1,745)
Common stock issued under stock plans, net of shares withheld for taxes, Shares		1,296
Stock-based compensation	19,694		19,694
Other comprehensive income:
Translation adjustments	(912)				(912)
Net income	7,498			7,498
Balance at Mar. 31, 2020	$ 400,494	$ 661	$ 282,857	$ 119,119	$ (2,143)
Balance, Shares at Mar. 31, 2020		66,134