Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Restricted stock units	Performance share units	Common Stock	Common Stock Restricted stock units	Common Stock Performance share units	Additional paid in capital	Additional paid in capital Restricted stock units	Additional paid in capital Performance share units	Accumulated deficit	Accumulated other comprehensive income	Treasury Stock
Beginning Balance, Shares at May. 31, 2021				38,920,951,000
Beginning Balance at May. 31, 2021	$ 439,457			$ 377			$ 573,507			$ (131,866)	$ 3,153	$ (5,714)
Beginning Balance, Treasury Shares at May. 31, 2021												(370,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(6,972)									(6,972)
Exercise of stock options, Shares				80,635,000
Exercise of stock options	1,280			$ 1			1,279
Issuance/Cancellation of performance share units and restricted stock units, net, Shares					279,495,000	59,371,000
Issuance/Cancellation of performance share units and restricted stock units		$ (1,734)						$ (1,734)
Purchase of common stock under ESPP, Shares				49,789,000
Purchases of common stock under ESPP	900			$ 1			899
Stock-based compensation	2,429						2,429
Other comprehensive loss, net of tax	590										590
Ending Balance, Shares at Aug. 31, 2021				39,390,241,000
Ending Balance at Aug. 31, 2021	$ 435,950			$ 379			576,380			(138,838)	3,743	$ (5,714)
Ending Balance, Treasury Shares at Aug. 31, 2021												(370,000,000)
Beginning Balance, Shares at May. 31, 2022	39,171,173			39,541,173
Beginning Balance at May. 31, 2022	$ 424,489			$ 380			586,879			(158,413)	1,357	$ (5,714)
Beginning Balance, Treasury Shares at May. 31, 2022												(370,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(13,004)
Exercise of stock options, Shares				6,617
Exercise of stock options	(29)						(29)
Issuance/Cancellation of performance share units and restricted stock units, net, Shares					213,241	29,826
Issuance/Cancellation of performance share units and restricted stock units		$ (648)	$ (312)					$ (648)	$ (312)
Purchase of common stock under ESPP, Shares				56,894
Purchases of common stock under ESPP	1,071			$ 1			1,070
Stock-based compensation	3,024						3,024
Other comprehensive loss, net of tax	$ (550)										(550)
Ending Balance, Shares at Aug. 31, 2022	39,477,751			39,847,751
Ending Balance at Aug. 31, 2022	$ 414,041			$ 381			$ 589,984			$ (171,417)	$ 807	$ (5,714)
Ending Balance, Treasury Shares at Aug. 31, 2022												(370,000)