Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Net operating losses	$ 93	$ 138
Warranty reserve	14,510	12,904
Stock-based compensation	2,186	1,554
Accruals not currently deductible and other	2,261	6,195
Inventories	5,785	4,406
State tax credit carryforwards	4,020	4,350
Gross deferred tax assets, before valuation allowance	28,855	29,547
Valuation allowance	(4,061)	(4,582)
Gross deferred tax assets, after valuation allowance	24,794	24,965
Deferred tax liabilities:
Depreciation and other	(25,688)	(20,426)
Gross deferred tax liabilities	(25,688)	(20,426)
Net deferred tax liability	$ (894)
Net deferred tax asset		$ 4,539