Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Line Items]
Income tax expense (benefit)	$ 50	$ (416)	$ 3,961	$ 1,379
Maximum | European Subsidiary
Income Tax Disclosure [Line Items]
Income tax expense (benefit)	$ 100
Aduro
Income Tax Disclosure [Line Items]
Income tax expense (benefit)		$ (400)	$ 4,000	$ 1,400