Annual report pursuant to Section 13 and 15(d)

Equity Incentive Plans and Stock Based Compensation - Stock Options Outstanding and Exercisable by Exercise Price (Detail)

v2.4.0.8
Equity Incentive Plans and Stock Based Compensation - Stock Options Outstanding and Exercisable by Exercise Price (Detail) (USD $)
 12 Months Ended
Dec. 31, 2013
$0.42 - 1.38 [Member]
  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit $ 0.42
Range of Exercise Prices, Upper Limit $ 1.38
Options Outstanding, Number Outstanding 570,518
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 4 years 2 months 19 days
Options Outstanding, Weighted Average Exercise Price $ 1.11
Options Exercisable, Number Exercisable 549,684
Options Exercisable, Weighted Average Exercise Price $ 1.10
$1.44 - 1.44 [Member]
  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit $ 1.44
Range of Exercise Prices, Upper Limit $ 1.44
Options Outstanding, Number Outstanding 1,377,739
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 6 years 3 months 29 days
Options Outstanding, Weighted Average Exercise Price $ 1.44
Options Exercisable, Number Exercisable 1,230,281
Options Exercisable, Weighted Average Exercise Price $ 1.44
$1.49 - 1.64 [Member]
  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit $ 1.49
Range of Exercise Prices, Upper Limit $ 1.64
Options Outstanding, Number Outstanding 1,124,003
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 7 years 4 months 10 days
Options Outstanding, Weighted Average Exercise Price $ 1.63
Options Exercisable, Number Exercisable 715,809
Options Exercisable, Weighted Average Exercise Price $ 1.63
$1.64 - 5.06 [Member]
  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit $ 1.64
Range of Exercise Prices, Upper Limit $ 5.06
Options Outstanding, Number Outstanding 667,309
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 8 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price $ 3.82
Options Exercisable, Number Exercisable 275,519
Options Exercisable, Weighted Average Exercise Price $ 3.13
$5.09 - 5.09 [Member]
  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit $ 5.09
Range of Exercise Prices, Upper Limit $ 5.09
Options Outstanding, Number Outstanding 1,185,000
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 9 years 2 months 9 days
Options Outstanding, Weighted Average Exercise Price $ 5.09
Options Exercisable, Number Exercisable 236,249
Options Exercisable, Weighted Average Exercise Price $ 5.09
$ 5.25 - 6.85 [Member]
  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit $ 5.25
Range of Exercise Prices, Upper Limit $ 6.85
Options Outstanding, Number Outstanding 690,937
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 8 years 6 months 29 days
Options Outstanding, Weighted Average Exercise Price $ 6.14
Options Exercisable, Number Exercisable 348,592
Options Exercisable, Weighted Average Exercise Price $ 6.22
$ 7.00 - 7.75 [Member]
  
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 $ 7.75
Options Outstanding, Number Outstanding 911,000
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 8 years 3 months 26 days
Options Outstanding, Weighted Average Exercise Price $ 7.26
Options Exercisable, Number Exercisable 366,536
Options Exercisable, Weighted Average Exercise Price $ 7.25
$ 0.42 - 7.75 [Member]
  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit $ 0.42
Range of Exercise Prices, Upper Limit $ 7.75
Options Outstanding, Number Outstanding 6,526,506
Options Outstanding, Weighted Average Remaining Contractual Life (Years) 7 years 6 months 22 days
Options Outstanding, Weighted Average Exercise Price $ 3.66
Options Exercisable, Number Exercisable 3,722,760
Options Exercisable, Weighted Average Exercise Price $ 2.80