Income Taxes - Schedule of Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Deferred tax assets: | ||
| Net operating loss carryforwards | $ 71,925 | $ 65,957 |
| Tax credit carryforwards | 4,947 | 4,533 |
| Accruals | 1,274 | 1,125 |
| Other | 1,088 | 698 |
| Gross deferred tax assets | 79,234 | 72,313 |
| Valuation allowance | (76,295) | (70,053) |
| Total deferred tax assets | 2,939 | 2,260 |
| Deferred tax liabilities: | ||
| Property and equipment | 195 | 95 |
| Purchased intangibles | (8,979) | (2,355) |
| Other | (212) | 0 |
| Total deferred tax liabilities | (8,996) | $ (2,260) |
| Net deferred tax liabilities | $ (6,057) |