Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Reserves and allowances not currently deductible for tax purposes	$ 13,495	$ 12,783
Basis difference related to fixed assets	5,342	5,946
Compensation and benefits	8,416	7,807
Basis difference for inventory valuation	1,784	1,612
Compensatory stock options and rights	3,988	3,869
Deferred revenue and other	120	175
Operating loss carryforwards	7,191	21,799
Tax credit carryforwards	54,219	62,668
Basis difference related to intangible assets with a definite life	12,767	7,061
Other	5,678	634
Total deferred tax assets	113,000	124,354
Valuation allowance for deferred tax assets	(13,408)	(11,114)
Deferred tax assets, net of valuation allowance	99,592	113,240
Deferred tax liabilities:
Prepaid expenses	(1,181)	(773)
Basis difference related to intangible assets with an indefinite life	(25,128)	(22,891)
Total deferred tax liabilities	(26,309)	(23,664)
Net deferred tax assets	73,283	89,576
Net deferred tax assets are shown on the accompanying consolidated balance sheets as follows:
Non-current deferred tax assets	75,079	91,398
Non-current deferred tax liabilities	$ (1,796)	$ (1,822)