Stockholders' Equity - Additional Information (Detail)
|
12 Months Ended |
|
|
Dec. 31, 2016
USD ($)
Plan
$ / shares
shares
|
Dec. 31, 2015
USD ($)
$ / shares
shares
|
Dec. 31, 2014
USD ($)
$ / shares
shares
|
Jun. 30, 2015
shares
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Preferred stock, shares authorized |
10,000,000
|
10,000,000
|
|
|
| Preferred stock, shares outstanding |
0
|
0
|
|
|
| Common stock, shares authorized |
40,000,000
|
40,000,000
|
|
|
| Common stock, shares outstanding |
14,388,728
|
14,388,728
|
|
|
| Number of equity incentive plans | Plan |
2
|
|
|
|
| Shares outstanding under equity incentive plans |
1,075,000
|
1,257,000
|
|
|
| Term of vesting schedule |
10 years
|
|
|
|
| Vested share exercised |
3 months
|
|
|
|
| Fair value assumption, risk-free interest rates |
|
1.94%
|
1.56%
|
|
| Fair value assumption, expected dividend yields |
|
0.00%
|
0.00%
|
|
| Stock options granted under equity incentive plans |
0
|
|
|
|
| Aggregate intrinsic value in outstanding stock options | $ |
$ 0
|
|
|
|
| Aggregate intrinsic value closing stock price | $ / shares |
$ 0.38
|
|
|
|
| Fair value of options granted | $ / shares |
|
$ 1.25
|
$ 0.93
|
|
| Stock issued during period, stock options exercised |
0
|
30,000
|
174,000
|
|
| Cash received from exercise of stock options | $ |
|
$ 27,000
|
$ 137,000
|
|
| Stock options exercise price | $ / shares |
|
$ 0.89
|
$ 0.79
|
|
| Unrecognized compensation expense related to non-vested stock options | $ |
$ 123,000
|
|
|
|
| Recognition of unrecognized compensation expense, weighted-average period (in years) |
10 months 24 days
|
|
|
|
| Fair value of options that vested | $ |
$ 302,000
|
$ 205,000
|
$ 80,000
|
|
| Maximum [Member] |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Period of option granted vest |
3 years
|
|
|
|
| Fair value assumption, expected term (years) |
|
6 years
|
6 years
|
|
| Fair value assumption, expected volatility |
|
96.65%
|
96.65%
|
|
| Minimum [Member] |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Period of option granted vest |
2 years
|
|
|
|
| Fair value assumption, expected term (years) |
|
4 years
|
4 years
|
|
| Fair value assumption, expected volatility |
|
93.41%
|
93.41%
|
|
| 2006 Equity Incentive Plan [Member] |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Shares outstanding under equity incentive plans |
810,000
|
|
|
|
| Common stock available for future issuance |
0
|
|
|
|
| Share-based compensation arrangement by share-based payment award, award vesting rights, percentage |
100.00%
|
|
|
|
| 2015 Equity Incentive Plan [Member] |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Shares outstanding under equity incentive plans |
265,000
|
|
|
|
| Common stock available for future issuance |
1,080,000
|
|
|
|
| Common stock authorized for issuance there-under |
|
|
|
1,205,749
|
| 2015 Equity Incentive Plan [Member] | Maximum [Member] |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Common stock available for future issuance |
958,668
|
|
|
|