Loss per Share - Amounts Used in Computing (Loss) Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net loss	$ (3,589)	$ (4,048)	$ (3,791)	$ (1,736)	$ (210)	$ (1,934)	$ (3,248)	$ (2,958)	$ (13,164)	$ (8,350)	$ (11,721)
Denominator:
Weighted average shares outstanding - basic and diluted (in shares)									23,037,000	22,801,000	22,615,000
Loss per share - basic and diluted:
Net loss per share (in dollars per share)	$ (0.15)	$ (0.18)	$ (0.16)	$ (0.08)	$ (0.01)	$ (0.08)	$ (0.14)	$ (0.13)	$ (0.57)	$ (0.37)	$ (0.52)
Anti-dilutive stock options, SSARs, restricted shares and performance shares									1,433,000	756,000	1,004,000
Outstanding weighted average basic shares, number of excluded restricted shares and performance shares									300,437	334,817	490,355