Variable Interest Entities - Summary of Revenues and Expenses Included in Consolidated Statements of Operations and Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Aug. 31, 2019	May 31, 2019	Aug. 31, 2018	May 31, 2018	Aug. 31, 2019	Aug. 31, 2018
Variable Interest Entity [Line Items]
Net sales	$ 90,246		$ 108,867		$ 183,700	$ 209,722
Cost of sales	66,477		77,804		133,922	150,982
Gross profit	23,769		31,063		49,778	58,740
Selling	8,701		9,604		18,582	20,298
General and administrative	17,782		17,038		35,207	33,150
Engineering and technical support	5,035		6,070		10,842	11,981
Total operating expenses	31,518		42,526		64,631	75,243
Operating loss	(7,749)		(11,463)		(14,853)	(16,503)
Interest and bank charges	(887)		(1,117)		(1,884)	(2,217)
Loss before income taxes	(6,049)		(14,164)		(11,066)	(17,829)
Income tax expense	1,115		8,338		(1,530)	7,225
Net loss	(7,164)	$ (2,372)	(22,502)	$ (2,552)	(9,536)	(25,054)
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net sales	253		93		274	216
Cost of sales	343		26		414	36
Gross profit	(90)		67		(140)	180
Selling	161		296		362	624
General and administrative	1,157		1,317		2,377	2,543
Engineering and technical support	1,354		1,828		2,719	3,618
Total operating expenses	2,672		3,441		5,458	6,785
Operating loss	(2,762)		(3,374)		(5,598)	(6,605)
Interest and bank charges	(315)		(982)		(615)	(1,887)
Loss before income taxes	(3,077)		(4,356)		(6,213)	(8,492)
Net loss	$ (3,077)		$ (4,356)		$ (6,213)	$ (8,492)