Unaudited Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Balance (in shares) at Mar. 31, 2020		40,713,000
Balance at Mar. 31, 2020	$ 63,127	$ 4,071	$ 176,209	$ (117,153)
Increase (Decrease) in Stockholders' Equity
Stock option exercises (in shares)		27,000
Stock option exercises	74	$ 3	71
Net income (loss)	10,348			10,348
Stock-based compensation	607		607
Issuance of shares pursuant to vesting of restricted stock units, net of payroll withholding taxes (in shares)		12,000
Issuance of shares pursuant to vesting of restricted stock units, net of payroll withholding taxes	0	$ 1	(1)
Balance (in shares) at Jun. 30, 2020		40,752,000
Balance at Jun. 30, 2020	74,156	$ 4,075	176,886	(106,805)
Balance (in shares) at Mar. 31, 2020		40,713,000
Balance at Mar. 31, 2020	63,127	$ 4,071	176,209	(117,153)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	10,761
Balance (in shares) at Sep. 30, 2020		41,110,000
Balance at Sep. 30, 2020	76,046	$ 4,111	178,327	(106,392)
Balance (in shares) at Jun. 30, 2020		40,752,000
Balance at Jun. 30, 2020	74,156	$ 4,075	176,886	(106,805)
Increase (Decrease) in Stockholders' Equity
Stock option exercises (in shares)		239,000
Stock option exercises	622	$ 24	598
Net income (loss)	413			413
Issuance of shares pursuant to Employee Stock Purchase Plan (in shares)		42,000
Issuance of shares pursuant to Employee Stock Purchase Plan	188	$ 4	184
Stock-based compensation	667		667
Issuance of shares pursuant to vesting of restricted stock units, net of payroll withholding taxes (in shares)		77,000
Issuance of shares pursuant to vesting of restricted stock units, net of payroll withholding taxes	0	$ 8	(8)
Balance (in shares) at Sep. 30, 2020		41,110,000
Balance at Sep. 30, 2020	$ 76,046	$ 4,111	178,327	(106,392)
Balance (in shares) at Mar. 31, 2021	41,687,000	41,687,000
Balance at Mar. 31, 2021	$ 78,979	$ 4,170	181,828	(107,019)
Increase (Decrease) in Stockholders' Equity
Stock option exercises (in shares)		473,000
Stock option exercises	1,375	$ 47	1,328
Net income (loss)	611			611
Stock-based compensation	794		794
Balance (in shares) at Jun. 30, 2021		42,160,000
Balance at Jun. 30, 2021	$ 81,759	$ 4,217	183,950	(106,408)
Balance (in shares) at Mar. 31, 2021	41,687,000	41,687,000
Balance at Mar. 31, 2021	$ 78,979	$ 4,170	181,828	(107,019)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	$ (1,536)
Balance (in shares) at Sep. 30, 2021	42,333,000	42,333,000
Balance at Sep. 30, 2021	$ 80,538	$ 4,234	184,859	(108,555)
Balance (in shares) at Jun. 30, 2021		42,160,000
Balance at Jun. 30, 2021	81,759	$ 4,217	183,950	(106,408)
Increase (Decrease) in Stockholders' Equity
Stock option exercises (in shares)		15,000
Stock option exercises	32	$ 1	31
Net income (loss)	(2,147)			(2,147)
Issuance of shares pursuant to Employee Stock Purchase Plan (in shares)		44,000
Issuance of shares pursuant to Employee Stock Purchase Plan	239	$ 4	235
Stock-based compensation	834		834
Issuance of shares pursuant to vesting of restricted stock units, net of payroll withholding taxes (in shares)		114,000
Issuance of shares pursuant to vesting of restricted stock units, net of payroll withholding taxes	$ (179)	$ 12	(191)
Balance (in shares) at Sep. 30, 2021	42,333,000	42,333,000
Balance at Sep. 30, 2021	$ 80,538	$ 4,234	$ 184,859	$ (108,555)