Variable Interest Entities - Summary of Revenues and Expenses Included in Consolidated Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Aug. 31, 2020	May 31, 2020	Aug. 31, 2019	May 31, 2019	Aug. 31, 2020	Aug. 31, 2019
Variable Interest Entity [Line Items]
Net sales	$ 128,032		$ 90,246		$ 200,019	$ 183,700
Cost of sales	89,956		66,477		141,968	133,922
Gross profit	38,076		23,769		58,051	49,778
Selling	9,067		8,701		17,429	18,582
General and administrative	15,545		17,782		30,540	35,207
Engineering and technical support	4,781		5,035		9,266	10,842
Total operating expenses	29,393		31,518		57,235	64,631
Operating income (loss)	8,683		(7,749)		816	(14,853)
Interest and bank charges	(1,010)		(887)		(1,863)	(1,884)
Total other income, net	481		1,700		1,024	3,787
Income (loss) before income taxes	9,164		(6,049)		1,840	(11,066)
Income tax expense	2,609		1,115		4,390	(1,530)
Net income (loss)	6,555	$ (9,105)	(7,164)	$ (2,372)	(2,550)	(9,536)
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net sales	263		253		360	274
Cost of sales	262		343		381	414
Gross profit	1		(90)		(21)	(140)
Selling	125		161		302	362
General and administrative	428		1,157		857	2,377
Engineering and technical support	1,094		1,354		2,249	2,719
Total operating expenses	1,647		2,672		3,408	5,458
Operating income (loss)	(1,646)		(2,762)		(3,429)	(5,598)
Interest and bank charges	(368)		(315)		(722)	(615)
Total other income, net	(368)		(315)		(722)	(615)
Income (loss) before income taxes	(2,014)		(3,077)		(4,151)	(6,213)
Net income (loss)	$ (2,014)		$ (3,077)		$ (4,151)	$ (6,213)