Income Taxes - Components of Net Deferred Tax Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Acquisition-related costs	$ 441	$ 502
Deferred revenues	2,300	1,927
Allowance for doubtful accounts	1,274	887
Inventory	1,709	1,350
Deferred compensation	2,614	2,665
Bonus accrual	874	655
Vacation accrual	191	203
Deferred rent	551	625
Warranty accrual	1,374	970
Accrued expenses	466	454
Satellite network and other property	8,051	10,852
Foreign tax credit	1,487	1,618
Alternative minimum tax credit	325	325
Tax loss carryforwards and credits	29,129	20,628
Other	12	4
Total deferred tax assets	50,798	43,665
Deferred tax liabilities:
Intangible assets	(15,292)	(18,431)
Goodwill	(5,035)	(2,429)
Total deferred tax liabilities	(20,327)	(20,860)
Net deferred tax assets before valuation allowance	30,471	22,805
Less valuation allowance	(46,471)	(40,347)
Net deferred tax assets (liabilities)	(16,000)	(17,542)
Deferred tax assets, non-current	109	104
Deferred tax liabilities, non-current	$ (16,109)	$ (17,646)