Income Taxes - Additional Information (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Income Tax Disclosure [Line Items] | |||
| Income tax federal statutory rate | 34.00% | 34.00% | 34.00% |
| Deferred tax provision | $ 0.1 | $ 0.1 | $ 0.1 |
| Net operating loss carryforwards, federal | 99.5 | ||
| Net operating loss carryforwards, state | 71.2 | ||
| Net operating loss carryforwards, foreign | 21.8 | ||
| Stock options | $ 4.4 | ||
| Income tax examination, description | The statute of limitations for these jurisdictions is generally three to six years | ||
| Deferred Tax Assets Operating Loss Carryforwards [Member] | |||
| Income Tax Disclosure [Line Items] | |||
| Increase in valuation allowance | $ 13.0 | ||
| Domestic Tax Authority [Member] | |||
| Income Tax Disclosure [Line Items] | |||
| Research and development credit carryforwards | 1.1 | ||
| State and Local Jurisdiction [Member] | |||
| Income Tax Disclosure [Line Items] | |||
| Research and development credit carryforwards | $ 0.2 | ||