Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2019	Aug. 31, 2018
Disaggregation Of Revenue [Line Items]
Net sales	$ 90,246	$ 108,867	$ 183,700	$ 209,722
Corporate, Non-Segment [Member]
Disaggregation Of Revenue [Line Items]
Net sales	113	349	266	426
Automotive [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Net sales	26,845	40,006	56,487	79,652
Automotive [Member] | Operating Segments [Member] | OEM Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	11,810	23,225	26,763	46,310
Automotive [Member] | Operating Segments [Member] | Aftermarket Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	15,035	16,781	29,724	33,342
Consumer Electronics [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Net sales	63,034	68,328	126,687	129,232
Consumer Electronics [Member] | Operating Segments [Member] | Premium Audio Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	38,108	39,652	74,806	72,041
Consumer Electronics [Member] | Operating Segments [Member] | Other Consumer Electronic Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	24,926	28,676	51,881	57,191
Biometrics [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Net sales	254	184	260	412
Biometrics [Member] | Operating Segments [Member] | Biometric Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	$ 254	$ 184	$ 260	$ 412