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Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents maturity period, maximum	90 days
Income tax expense	$ 1.0
ASU 2016-09 [Member]
Summary Of Significant Accounting Policies [Line Items]
Income tax expense	$ 1.0
Decrease in earnings per share basic and diluted \| $ / shares	$ 0.01