Condensed Consolidated Statements of Shareholders' Equity - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Beginning balance at Mar. 31, 2019	$ 188,000	$ 215,047,000	$ 71,407,000	$ (6,887,000)	$ 279,755,000
Beginning balance (in shares) at Mar. 31, 2019	18,817,400
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation recognized under employee stock plans	$ 0	988,000	0	0	988,000
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes	$ 1,000	(363,000)	0	0	(362,000)
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes (in shares)	36,872
Foreign currency translation	$ 0	0	0	599,000	599,000
Net (loss) income	0	0	(6,151,000)	0	(6,151,000)
Ending balance at Jun. 30, 2019	$ 189,000	215,672,000	65,256,000	(6,288,000)	274,829,000
Ending balance (in shares) at Jun. 30, 2019	18,854,272
Beginning balance at Mar. 31, 2019	$ 188,000	215,047,000	71,407,000	(6,887,000)	279,755,000
Beginning balance (in shares) at Mar. 31, 2019	18,817,400
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation					1,183,000
Net (loss) income					903,000
Ending balance at Dec. 31, 2019	$ 190,000	217,530,000	72,310,000	(5,704,000)	284,326,000
Ending balance (in shares) at Dec. 31, 2019	18,965,030
Beginning balance at Jun. 30, 2019	$ 189,000	215,672,000	65,256,000	(6,288,000)	274,829,000
Beginning balance (in shares) at Jun. 30, 2019	18,854,272
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation recognized under employee stock plans	$ 0	1,053,000	0	0	1,053,000
Exercise of stock options	$ 0	405,000	0	0	405,000
Exercise of stock options (in shares)	52,800
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes	$ 0	(700,000)	0	0	(700,000)
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes (in shares)	37,814
Foreign currency translation	$ 0	0	0	(431,000)	(431,000)
Net (loss) income	0	0	6,189,000	0	6,189,000
Ending balance at Sep. 30, 2019	$ 189,000	216,430,000	71,445,000	(6,719,000)	281,345,000
Ending balance (in shares) at Sep. 30, 2019	18,944,886
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation recognized under employee stock plans	$ 0	1,071,000	0	0	1,071,000
Exercise of stock options	$ 1,000	29,000	0	0	30,000
Exercise of stock options (in shares)	3,600
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes	$ 0	0	0	0	0
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes (in shares)	16,544
Foreign currency translation	$ 0	0	0	1,015,000	1,015,000
Net (loss) income	0	0	865,000	0	865,000
Ending balance at Dec. 31, 2019	$ 190,000	217,530,000	72,310,000	(5,704,000)	284,326,000
Ending balance (in shares) at Dec. 31, 2019	18,965,030
Beginning balance at Mar. 31, 2020	$ 190,000	218,581,000	64,117,000	(7,368,000)	$ 275,520,000
Beginning balance (in shares) at Mar. 31, 2020	18,969,380				18,969,380
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation recognized under employee stock plans	$ 0	1,043,000	0	0	$ 1,043,000
Exercise of stock options	$ 0	20,000	0	0	20,000
Exercise of stock options (in shares)	3,000
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes	$ 0	(207,000)	0	0	(207,000)
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes (in shares)	29,953
Foreign currency translation	$ 0	0	0	(1,263,000)	(1,263,000)
Net (loss) income	0	0	(3,012,000)	0	(3,012,000)
Ending balance at Jun. 30, 2020	$ 190,000	219,437,000	61,105,000	(8,631,000)	272,101,000
Ending balance (in shares) at Jun. 30, 2020	19,002,333
Beginning balance at Mar. 31, 2020	$ 190,000	218,581,000	64,117,000	(7,368,000)	$ 275,520,000
Beginning balance (in shares) at Mar. 31, 2020	18,969,380				18,969,380
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation					$ (90,000)
Net (loss) income					20,641,000
Ending balance at Dec. 31, 2020	$ 191,000	222,193,000	84,758,000	(7,458,000)	$ 299,684,000
Ending balance (in shares) at Dec. 31, 2020	19,056,292				19,056,292
Beginning balance at Jun. 30, 2020	$ 190,000	219,437,000	61,105,000	(8,631,000)	$ 272,101,000
Beginning balance (in shares) at Jun. 30, 2020	19,002,333
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation recognized under employee stock plans	$ 0	1,218,000	0	0	1,218,000
Exercise of stock options	$ 0	73,000	0	0	73,000
Exercise of stock options (in shares)	6,000
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes	$ 0	(140,000)	0	0	(140,000)
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes (in shares)	18,254
Foreign currency translation	$ 0	0	0	(441,000)	(441,000)
Net (loss) income	0	0	15,184,000	0	15,184,000
Ending balance at Sep. 30, 2020	$ 190,000	220,588,000	76,289,000	(9,072,000)	287,995,000
Ending balance (in shares) at Sep. 30, 2020	19,026,587
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation recognized under employee stock plans	$ 0	1,498,000	0	0	1,498,000
Exercise of stock options	$ 0	112,000	0	0	112,000
Exercise of stock options (in shares)	5,794
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes	$ 1,000	(5,000)	0	0	(4,000)
Issuance of common stock upon vesting of RSUs, net of shares withheld for employee taxes (in shares)	23,911
Foreign currency translation	$ 0	0	0	1,614,000	1,614,000
Net (loss) income	0	0	8,469,000	0	8,469,000
Ending balance at Dec. 31, 2020	$ 191,000	$ 222,193,000	$ 84,758,000	$ (7,458,000)	$ 299,684,000
Ending balance (in shares) at Dec. 31, 2020	19,056,292				19,056,292