Interim Condensed Consolidated Financial Statements - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Cash and cash equivalents	$ 21,759	$ 20,994	$ 13,470	$ 13,901