Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Tax expense resulting from share-based compensation tax benefits	$ 1,400	$ 6,900	$ 8,000
Deferred tax assets, state NOLs	1,800
Deferred tax assets, federal NOLs	900
Research and development tax credit studies	14,100
Liability for unrecognized tax benefits		3,900
Threshold to favorably impact effective tax rate	4,100
Unrecognized tax benefits, accrued interest	98	$ 55
ARIZONA | 2019
Income Tax Contingency [Line Items]
Minimum tax credit carryover	1,200
AUSTRALIA
Income Tax Contingency [Line Items]
Deferred tax assets, foreign NOLs	1,500
UNITED KINGDOM
Income Tax Contingency [Line Items]
Deferred tax assets, foreign NOLs	5,500
CANADA
Income Tax Contingency [Line Items]
Deferred tax assets, foreign NOLs	700
GERMANY
Income Tax Contingency [Line Items]
Deferred tax assets, foreign NOLs	1,100
Federal
Income Tax Contingency [Line Items]
Federal research and development credit carry forwards	43
State
Income Tax Contingency [Line Items]
Liability for unrecognized tax benefits	200
State | ARIZONA
Income Tax Contingency [Line Items]
State research and development credit carry forwards	$ 6,400