Stock Based Compensation - Additional Information (Detail) - USD ($)
|
12 Months Ended |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
| Total stock-based compensation expense |
$ 990,000
|
$ 1,902,000
|
$ 3,159,000
|
| Common stock reserved |
2,370,000
|
|
|
| Shares reserved for future issuance |
1,988,797
|
|
|
| Maximum term of options granted |
10 years
|
|
|
| Number of options to be granted to any one individual |
1,300,000
|
|
|
| Number of underlying shares exercisable |
808,639
|
688,468
|
603,717
|
| Weighted average exercise price of options exercisable |
$ 23.43
|
$ 26.81
|
$ 28.94
|
| Weighted average remaining contractual term of options outstanding |
6 years 6 months
|
|
|
| Weighted average remaining contractual term of options exercisable |
5 years 4 months 24 days
|
|
|
| Weighted average remaining contractual term of vested and unvested options expected to vest |
6 years 4 months 24 days
|
|
|
| Aggregate intrinsic value of options outstanding |
$ 0
|
|
|
| Aggregate intrinsic value of options exercisable |
0
|
|
|
| Unrecognized compensation cost related to unvested options |
$ 500,000
|
|
|
| Unvested stock-based awards expected to be recognized, weighted-average period |
1 year 4 months 21 days
|
|
|
| Weighted average grant-date fair value of options granted |
$ 1.85
|
$ 5.08
|
$ 7.28
|
| Number of options exercised |
0
|
0
|
0
|
| Shares available for grant |
689,012
|
|
|
| Aggregate grant-date fair value of RSUs vested |
$ 800,000
|
$ 1,000,000
|
$ 800,000
|
| Common stock underlying RSUs that were fully vested |
52,477
|
|
|
| Restricted stock units (RSUs) [Member] |
|
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
| Total stock-based compensation expense |
$ 300,000
|
$ 800,000
|
$ 1,100,000
|
| Aggregate RSUs granted |
0
|
78,843
|
82,800
|
| Unvested stock-based awards expected to be recognized, weighted-average period |
1 year 3 months 7 days
|
|
|
| Aggregate grant-date fair value of RSUs granted |
$ 0
|
$ 800,000
|
$ 1,200,000
|
| Total unrecognized compensation cost related to unvested RSUs |
$ 100,000
|
|
|
| Share-based Compensation Award, Tranche One [Member] |
|
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
| Percentage of options vested |
25.00%
|
|
|
| Share-based Compensation Award, Tranche One [Member] | Restricted stock units (RSUs) [Member] |
|
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
| Percentage of options vested |
25.00%
|
|
|