- Reconciliation of Federal Statutory Income Tax Rate to Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	21.00%	35.00%
State income taxes, net of federal benefit	2.30%	1.90%	1.40%
Domestic manufacturing deduction	(2.10%)	(1.40%)	(0.50%)
Research and development tax credit	(4.00%)	(3.10%)	(5.60%)
Stock based compensation	0.20%	(1.40%)	(4.40%)
Valuation allowance	0.50%	0.20%	1.20%
Tax Reform impact	0.00%	0.40%	17.40%
Non-deductible expenses	0.00%	0.00%	2.00%
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent	1.70%	1.30%	(0.30%)
Other permanent differences	1.00%	3.00%	(0.30%)
Effective income tax rate for continuing operations	20.60%	21.90%	45.90%