CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Mar. 31, 2020
Statement of Financial Position [Abstract]
Accounts receivable, allowances	$ 350	$ 443
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	137,504,000	135,927,000
Common stock, shares outstanding (in shares)	115,083,000	113,506,000
Treasury stock, shares (in shares)	22,421,000	22,421,000