Annual report pursuant to Section 13 and 15(d)

Goodwill and Intangible Assets - Intangible Assets (Details)

v3.20.1
Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($)
$ in Thousands
12 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Mar. 31, 2018
Amortizing Intangibles:      
Finite-Lived Trademarks, Gross $ 15,315 $ 15,151  
Goodwill 41,210 40,294 $ 40,294
Trademarks 15,315 15,151  
Indefinite-lived Intangible Assets (Excluding Goodwill) 18,315 15,151  
Carrying Amount 64,893 64,726  
Accumulated Amortization (30,495) (26,128)  
Total amortization 34,398 38,598  
Amortization of Intangible Assets 4,500 4,500 4,300
Intangible Assets, Net (Including Goodwill) 52,713 53,749  
Intangible assets 83,208 79,877  
Patents [Member]      
Amortizing Intangibles:      
Finite-Lived Patents, Gross 26,662 26,662  
Accumulated Amortization (13,466) (12,046)  
Total amortization 13,196 14,616  
Amortization of Intangible Assets $ 1,400 $ 1,400 1,400
Patents [Member] | Minimum      
Amortizing Intangibles:      
Useful life 10 years 10 years  
Patents [Member] | Maximum [Member]      
Amortizing Intangibles:      
Useful life 18 years 18 years  
Customer Relationships      
Amortizing Intangibles:      
Useful life 12 years 2 months 12 days 12 years 3 months 12 days  
Accumulated Amortization $ (16,826) $ (13,868)  
Total amortization 21,202 23,982  
Finite-Lived Customer Relationships, Gross 38,028 37,850  
Amortization of Intangible Assets $ 3,100 $ 3,100 $ 2,900
Customer Relationships | Minimum      
Amortizing Intangibles:      
Useful life 10 years 10 years  
Customer Relationships | Maximum [Member]      
Amortizing Intangibles:      
Useful life 21 years 21 years  
Other Intangible Assets [Member]      
Amortizing Intangibles:      
Accumulated Amortization $ (203) $ (214)  
Total amortization 0 0  
Other Finite-Lived Intangible Assets, Gross $ 203 $ 214  
Purchased technology, customer relationships and patents | Weighted Average [Member]      
Amortizing Intangibles:      
Useful life 15 years 9 months 18 days 15 years 9 months 6 days  
Unclassified Indefinite-lived Intangible Assets [Member]      
Amortizing Intangibles:      
Indefinite-lived Intangible Assets (Excluding Goodwill) $ 3,000 $ 0  
KEMET Jianghai Electronics Components Co., Ltd (“KEMET Jianghai”)      
Amortizing Intangibles:      
NTS' sales to KEMET $ 2,131 $ 56