Income Taxes - Additional Information (Detail) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2015 |
Jun. 30, 2014 |
Jun. 30, 2015 |
Jun. 30, 2014 |
|
| Income Taxes [Line Items] | ||||
| Ownership change percentage criteria under Section 382 of the Internal Revenue Code | 50.00% | |||
| Testing period | 3 years | |||
| Valuation allowance related to net deferred tax | $ (1.3) | $ (4.1) | $ 1.8 | $ (3.0) |
| State | ||||
| Income Taxes [Line Items] | ||||
| State and Federal Operating loss carry-forwards | 399.0 | 399.0 | ||
| State Tax credit carry-forwards | 2.6 | $ 2.6 | ||
| State and Federal Operating loss carry-forwards expiration year | 2032 | |||
| Federal | ||||
| Income Taxes [Line Items] | ||||
| State and Federal Operating loss carry-forwards | $ 256.6 | $ 256.6 | ||
| State and Federal Operating loss carry-forwards expiration year | 2033 | |||