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, 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 (loss)	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 (loss)	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 (loss)	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
Balance at Mar. 31, 2020	400,494	$ 661	282,857	119,119	(2,143)
Balance, Shares at Mar. 31, 2020		66,134
Common stock issued under stock plans, net of shares withheld for taxes	(1,408)	$ 6	(1,414)
Common stock issued under stock plans, net of shares withheld for taxes, Shares		535
Stock-based compensation	5,393		5,393
Other comprehensive income:
Translation adjustments	(13)				(13)
Net income (loss)	(824)			(824)
Balance at Jun. 30, 2020	403,642	$ 667	286,836	118,295	(2,156)
Balance, Shares at Jun. 30, 2020		66,669
Balance at Mar. 31, 2020	400,494	$ 661	282,857	119,119	(2,143)
Balance, Shares at Mar. 31, 2020		66,134
Other comprehensive income:
Translation adjustments	89
Net income (loss)	9,631
Balance at Sep. 30, 2020	419,591	$ 667	292,228	128,750	(2,054)
Balance, Shares at Sep. 30, 2020		66,734
Balance at Jun. 30, 2020	403,642	$ 667	286,836	118,295	(2,156)
Balance, Shares at Jun. 30, 2020		66,669
Common stock issued under stock plans, net of shares withheld for taxes	(45)		(45)
Common stock issued under stock plans, net of shares withheld for taxes, Shares		65
Stock-based compensation	5,437		5,437
Other comprehensive income:
Translation adjustments	102				102
Net income (loss)	10,455			10,455
Balance at Sep. 30, 2020	$ 419,591	$ 667	$ 292,228	$ 128,750	$ (2,054)
Balance, Shares at Sep. 30, 2020		66,734