Income Taxes - Additional Information (Detail) - USD ($)
|
12 Months Ended |
Dec. 31, 2016 |
Dec. 31, 2015 |
| Income Tax Disclosure [Line Items] |
|
|
| Valuation allowance |
$ (54,310,000)
|
$ (49,514,000)
|
| Net operating loss carryforwards federal |
124,000,000
|
|
| Net operating loss carryforwards state |
75,200,000
|
|
| Cumulative unrealized excess tax deductions |
7,100,000
|
6,900,000
|
| Undistributed earnings from foreign subsidiaries |
$ 0
|
$ 0
|
| Minimum |
|
|
| Income Tax Disclosure [Line Items] |
|
|
| Operating loss carryforwards, expiration period |
2019
|
|
| Maximum |
|
|
| Income Tax Disclosure [Line Items] |
|
|
| Operating loss carryforwards, expiration period |
2036
|
|
| Federal |
|
|
| Income Tax Disclosure [Line Items] |
|
|
| Research and development tax credit carryforwards |
$ 1,500,000
|
|
| Federal | Minimum |
|
|
| Income Tax Disclosure [Line Items] |
|
|
| Research and development tax credit carryforwards, expiration period |
2019
|
|
| Federal | Maximum |
|
|
| Income Tax Disclosure [Line Items] |
|
|
| Research and development tax credit carryforwards, expiration period |
2036
|
|
| State | Indefinite Life |
|
|
| Income Tax Disclosure [Line Items] |
|
|
| Research and development tax credit carryforwards |
$ 1,200,000
|
|