Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Net operating losses	$ 7,666	$ 12,731
Intangible assets	42,853
Research and development credits	8,211	27,257
Depreciation	6,321	5,571
Valuation reserves and accrued liabilities	4,849	6,020
Foreign tax credit	376
Stock compensation	4,128	3,955
Inventory	1,069	2,062
Patents	150	163
Defined benefit obligation	1,796	1,977
Other credits	1,291	589
Unrealized foreign currency exchange loss		2,556
Other	2,499	36
Deferred tax assets, gross	81,209	62,917
Valuation allowance	(9,977)	(27,578)
Deferred tax liabilities:
Intangible assets		(2,925)
Unrealized foreign currency exchange gains	(554)
Undistributed profits of subsidiary	(4,352)	(6,450)
Property and equipment	(2,896)	(1,611)
Other	(583)	(548)
Deferred tax liabilities, gross	(8,385)	(11,534)
Net deferred tax asset	$ 62,847	$ 23,805