Annual report pursuant to Section 13 and 15(d)

Property, Plant and Equipment - Additional Information (Detail)

v3.8.0.1
Property, Plant and Equipment - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Mar. 31, 2016
Property Plant And Equipment [Abstract]      
Depreciation expense $ 1,986 $ 2,092 $ 2,201