Cash Proceeds Along with Fair Value Disclosures Related to Grants, Exercises, and Vesting Options (Detail) - USD ($) $ / shares in Units, $ in Thousands |
12 Months Ended | ||||
|---|---|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
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| Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |||||
| Proceeds from stock options exercised | $ 1 | $ 44 | $ 312 | ||
| Intrinsic value of stock options exercised | [1] | $ 52 | $ 108 | ||
| Weighted-average fair value of options granted | $ 1.03 | $ 1.54 | $ 1.61 | ||
| Total fair value of shares vested during the year | $ 1,728 | $ 2,268 | $ 1,208 | ||
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