Summary of Significant Accounting Policies - Schedule of Net Income (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net income (loss)	$ (53,545)	$ (36,520)	$ 28,504
Denominator:
Weighted average shares outstanding for basic income per common share (in shares)	8,964	9,108	9,074
Effect of dilutive stock options (in shares)	0	0	41
Adjusted weighted average shares outstanding for diluted income per common share (in shares)	8,964	9,108	9,115
Basic net income per common share (in dollars per share)	$ (5.97)	$ (4.01)	$ 3.14
Diluted net income per common share (in dollars per share)	$ (5.97)	$ (4.01)	$ 3.13