Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
LTIPs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4,922	$ 3,938	$ 2,551
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	7,162	8,928	5,106
Cost of sales | LTIPs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,658	1,254	654
Cost of sales | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2,185	1,502	865
Selling, general and administrative expenses | LTIPs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2,972	2,413	1,695
Selling, general and administrative expenses | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	4,831	7,338	4,195
Research and development | LTIPs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	292	271	202
Research and development | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 146	$ 88	$ 46