Interim Consolidated Financial Statements - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Summary Of Significant Accounting Policy [Line Items]
Tax withholding in financing activities	$ 56,000	$ 25,000
ASU No. 2016-09 [Member]
Summary Of Significant Accounting Policy [Line Items]
Cumulative effect adjustment to increase or (reduce) retained earnings			$ 200,000
Tax withholding in financing activities	$ 100,000
Change in reclassification of tax withholding		$ 39,000
Early Adoption of ASU No. 2016-16 [Member]
Summary Of Significant Accounting Policy [Line Items]
Cumulative effect adjustment to increase or (reduce) retained earnings			$ (500,000)