Annual report pursuant to Section 13 and 15(d)

Options Outstanding and Exercisable (Detail)

v3.3.1.900
Options Outstanding and Exercisable (Detail)
 12 Months Ended
Dec. 31, 2015
$ / shares
shares
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Options Outstanding Number of Shares | shares 4,493,000
Options Outstanding Weighted Average Exercise Price $ 2.72
Options Outstanding Weighted Average Remaining Life (Years) 6 years 7 months 2 days
Options Exercisable Number of Shares | shares 2,739,000
Options Exercisable Weighted Average Exercise Price $ 2.96
Range One  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 0.82
Range of Exercise Prices, Upper Limit $ 1.99
Options Outstanding Number of Shares | shares 563,000
Options Outstanding Weighted Average Exercise Price $ 1.54
Options Outstanding Weighted Average Remaining Life (Years) 6 years 11 months 23 days
Options Exercisable Number of Shares | shares 248,000
Options Exercisable Weighted Average Exercise Price $ 1.38
Range Two  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 2.00
Range of Exercise Prices, Upper Limit $ 2.99
Options Outstanding Number of Shares | shares 3,121,000
Options Outstanding Weighted Average Exercise Price $ 2.41
Options Outstanding Weighted Average Remaining Life (Years) 7 years 8 months 12 days
Options Exercisable Number of Shares | shares 1,767,000
Options Exercisable Weighted Average Exercise Price $ 2.41
Range Three  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 3.00
Range of Exercise Prices, Upper Limit $ 3.99
Options Outstanding Number of Shares | shares 118,000
Options Outstanding Weighted Average Exercise Price $ 3.16
Options Outstanding Weighted Average Remaining Life (Years) 2 years 6 months 4 days
Options Exercisable Number of Shares | shares 71,000
Options Exercisable Weighted Average Exercise Price $ 3.20
Range Four  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 4.00
Range of Exercise Prices, Upper Limit $ 4.99
Options Outstanding Number of Shares | shares 310,000
Options Outstanding Weighted Average Exercise Price $ 4.13
Options Outstanding Weighted Average Remaining Life (Years) 2 years 4 months 6 days
Options Exercisable Number of Shares | shares 293,000
Options Exercisable Weighted Average Exercise Price $ 4.11
Range Five  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 5.00
Range of Exercise Prices, Upper Limit $ 5.99
Options Outstanding Number of Shares | shares 286,000
Options Outstanding Weighted Average Exercise Price $ 5.07
Options Outstanding Weighted Average Remaining Life (Years) 1 year 10 months 24 days
Options Exercisable Number of Shares | shares 265,000
Options Exercisable Weighted Average Exercise Price $ 5.07
Range Six  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 6.00
Range of Exercise Prices, Upper Limit $ 6.99
Options Outstanding Number of Shares | shares 24,000
Options Outstanding Weighted Average Exercise Price $ 6.24
Options Outstanding Weighted Average Remaining Life (Years) 10 months 24 days
Options Exercisable Number of Shares | shares 24,000
Options Exercisable Weighted Average Exercise Price $ 6.24
Range Seven  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 7.00
Range of Exercise Prices, Upper Limit $ 7.99
Options Outstanding Number of Shares | shares 20,000
Options Outstanding Weighted Average Exercise Price $ 7.26
Options Outstanding Weighted Average Remaining Life (Years) 4 months 24 days
Options Exercisable Number of Shares | shares 20,000
Options Exercisable Weighted Average Exercise Price $ 7.26
Range Eight  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 8.00
Range of Exercise Prices, Upper Limit $ 8.75
Options Outstanding Number of Shares | shares 51,000
Options Outstanding Weighted Average Exercise Price $ 8.45
Options Outstanding Weighted Average Remaining Life (Years) 11 months 19 days
Options Exercisable Number of Shares | shares 51,000
Options Exercisable Weighted Average Exercise Price $ 8.45