Significant Agreements - Additional Information (Detail) - Supplemental Employee Retirement Plan [Member] $ in Millions |
3 Months Ended |
|---|---|
|
Mar. 31, 2017
USD ($)
| |
| Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items] | |
| Severance payment on effective date of retirement, as per the agreement | $ 1.2 |
| General and Administrative Expense [Member] | |
| Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items] | |
| Agreement Description | On March 25, 2016, the Company entered into a separation agreement and release of claims with its former Chief Executive Officer, Julia P. Gregory. Subject to Ms. Gregory’s continued compliance with restrictive covenants contained in her employment agreement with the Company, the separation agreement provides for Ms. Gregory to receive severance payments totaling $1.2 million for a period of 18 months following the effective date of Ms. Gregory’s retirement, the accelerated vesting of all unvested portions of stock option grants dated April 29, 2014 and February 8, 2016, and continued medical, dental and vision coverage paid for by the Company under the Company’s group healthcare plans for up to eighteen months following the effective date of Ms. Gregory’s retirement. The total amount of these charges was recognized as part of general and administrative expenses. Ms. Gregory will have a period of two years following the effective date of her retirement to exercise her vested Company stock options. |
| Separation Agreement Date | Mar. 25, 2016 |
| Stock option grant dates subject to accelerated vesting under agreement | April 29, 2014 and February 8, 2016 |
| Severance payments period following the effective date of retirement | 18 months |
| Health care period after retirement, as per the agreement | 18 months |
| Exercise period of vested stock options from retirement date, as per the agreement | 2 years |