Annual report pursuant to Section 13 and 15(d)

DESCRIPTION OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES Narrative (Details)

v3.20.1
DESCRIPTION OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES Narrative (Details)
12 Months Ended
Mar. 31, 2020
USD ($)
region
segment
Mar. 31, 2019
USD ($)
Mar. 31, 2018
USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]      
Research and development $ 36,301,000 $ 32,113,000 $ 38,562,000
Advertising expense 3,400,000 4,500,000 8,900,000
Shipping and handling fees $ 9,400,000 9,100,000 10,300,000
Number of reportable segments | segment 1    
Number of geographic regions | region 3    
Employer contributions $ 0 $ 0 $ 800,000
Minimum      
Concentration Risk [Line Items]      
Product warranty term 1 year    
Maximum      
Concentration Risk [Line Items]      
Product warranty term 3 years    
Accounts Receivable | Customer Concentration Risk      
Concentration Risk [Line Items]      
Concentration risk percentage 7.00% 21.00% 10.00%