Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
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	(202)	$ 2	(204)
Common stock issued under stock plans, net of shares withheld for taxes, Shares		225
Stock-based compensation	3,116		3,116
Cumulative effect adjustment related to the adoption of ASC 606	8,419			8,419
Other comprehensive income:
Translation adjustments	(499)				(499)
Net income	2,648			2,648
Balance at Jun. 30, 2018	336,892	$ 642	247,374	89,775	(899)
Balance, Shares at Jun. 30, 2018		64,220
Balance at Mar. 31, 2018	323,410	$ 640	244,462	78,708	(400)
Balance, Shares at Mar. 31, 2018		63,995
Other comprehensive income:
Translation adjustments	(1,292)
Net income	15,742
Balance at Sep. 30, 2018	355,434	$ 644	253,613	102,869	(1,692)
Balance, Shares at Sep. 30, 2018		64,382
Balance at Jun. 30, 2018	336,892	$ 642	247,374	89,775	(899)
Balance, Shares at Jun. 30, 2018		64,220
Common stock issued under stock plans, net of shares withheld for taxes	2,106	$ 2	2,104
Common stock issued under stock plans, net of shares withheld for taxes, Shares		162
Stock-based compensation	4,135		4,135
Other comprehensive income:
Translation adjustments	(793)				(793)
Net income	13,094			13,094
Balance at Sep. 30, 2018	355,434	$ 644	253,613	102,869	(1,692)
Balance, Shares at Sep. 30, 2018		64,382
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	(1,305)	$ 6	(1,311)
Common stock issued under stock plans, net of shares withheld for taxes, Shares		545
Stock-based compensation	4,891		4,891
Other comprehensive income:
Translation adjustments	54				54
Net income	1,244			1,244
Balance at Jun. 30, 2019	380,830	$ 654	268,488	112,865	(1,177)
Balance, Shares at Jun. 30, 2019		65,383
Balance at Mar. 31, 2019	375,946	$ 648	264,908	111,621	(1,231)
Balance, Shares at Mar. 31, 2019		64,838
Other comprehensive income:
Translation adjustments	(89)
Net income	7,325
Balance at Sep. 30, 2019	391,128	$ 654	272,848	118,946	(1,320)
Balance, Shares at Sep. 30, 2019		65,436
Balance at Jun. 30, 2019	380,830	$ 654	268,488	112,865	(1,177)
Balance, Shares at Jun. 30, 2019		65,383
Common stock issued under stock plans, net of shares withheld for taxes	44		44
Common stock issued under stock plans, net of shares withheld for taxes, Shares		53
Stock-based compensation	4,316		4,316
Other comprehensive income:
Translation adjustments	(143)				(143)
Net income	6,081			6,081
Balance at Sep. 30, 2019	$ 391,128	$ 654	$ 272,848	$ 118,946	$ (1,320)
Balance, Shares at Sep. 30, 2019		65,436