Basis of Presentation - Additional Information (Detail) $ in Thousands		3 Months Ended
	Jul. 31, 2018 Segment	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of operating segments | Segment	2
Net foreign exchange gains (losses) resulting from foreign currency transactions included in other income		$ 57	$ 69
Total right-of-use assets		1,493
Total lease liabilities		$ 1,635