Supplementary Financial Information - Earnings (loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income (loss) from continuing operations	$ (2,089)		$ 719		$ (1,460)	$ 1,137
Net income (loss) from discontinued operations, net of tax	(58)		(306)		(76)	9,624
Net income (loss)	$ (2,147)	$ 611	$ 413	$ 10,348	$ (1,536)	$ 10,761
Denominator:
Weighted average common shares used in basic computation	42,282,000		40,989,000		42,079,000	40,860,000
Dilutive stock options (in shares)	0		920,000		0	848,000
Weighted average common shares used in diluted computation	42,282,000		41,909,000		42,079,000	41,708,000
Basic:
Net income (loss) per share from continuing operations (in dollars per share)	$ (0.05)		$ 0.02		$ (0.03)	$ 0.03
Net income (loss) per share from discontinued operations (in dollars per share)	0.00		(0.01)		0.00	0.24
Net income (loss) per share (in dollars per share)	(0.05)		0.01		(0.03)	0.27
Diluted:
Net income (loss) per share from continuing operations (in dollars per share)	(0.05)		0.02		(0.03)	0.03
Net income (loss) per share from discontinued operations (in dollars per share)	(0.00)		(0.01)		0.00	0.23
Net income (loss) per share (in dollars per share)	$ (0.05)		$ 0.01		$ (0.03)	$ 0.26