Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Change in tax credit carryforwards		$ (2,001)	$ 113	$ 1,529
Tax benefit		2,313	(406)	(2,186)
Valuation allowance		84,822	71,815	45,983
Increase (decrease) in valuation allowance due to deferred tax assets		13,000	25,800	(3,600)
Research and development tax credits		11,480	22,082	9,045
Unrecognized tax benefits, if recognized, would affect the effective tax rate		700	700	$ 700
Benefits from share compensation		2,700
Research Tax Credit Carryforward [Member]
Income Taxes [Line Items]
Tax benefit		400	$ 400
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		$ 157,100
Net operating loss carryforwards expiration year		2018
Research and development tax credits		$ 11,600
Research and development tax credits beginning expiration year		2027
State [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		$ 91,600
Research and development tax credits		3,800
Foreign [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		$ 7,500
Net operating loss carryforwards expiration year		2022
Accounting Standards Update 2016-09 [Member] | Subsequent Event [Member]
Income Taxes [Line Items]
Increase (decrease) in valuation allowance due to deferred tax assets	$ 2,700