Summary of Significant Accounting Policies - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net income (loss)	$ 3,013	$ 6,992	$ (4,051)	$ 3,706
Denominator:
Weighted average shares outstanding for basic net income (loss) per common share (in shares)	9,109	9,076	9,099	9,065
Effect of dilutive stock options (in shares)	34	31	0	46
Adjusted weighted average shares outstanding for diluted net income (loss) per common share (in shares)	9,143	9,107	9,099	9,111
Basic net income (loss) per common share (in dollars per share)	$ 0.33	$ 0.77	$ (0.45)	$ 0.41
Diluted net income (loss) per common share (in dollars per share)	$ 0.33	$ 0.77	$ (0.45)	$ 0.41