Quarterly report pursuant to Section 13 or 15(d)

Cash Proceeds Along with Fair Value Disclosures Related to Grants, Exercises, and Vested Options (Detail)

v3.8.0.1
Cash Proceeds Along with Fair Value Disclosures Related to Grants, Exercises, and Vested Options (Detail) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Proceeds from stock options exercised $ 2  
Weighted-average fair value of options granted during period $ 0.29 $ 1.05
Total fair value of shares vested during the period $ 520 $ 334