Summary Information about Options Outstanding (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 5.20
Range of Exercise Prices, upper limit	$ 43.40
Options Number Outstanding	911,061
Options Outstanding Weighted Average Remaining Contractual Life (Years)	7 years 9 months
Options Outstanding Weighted Average Exercise Price	$ 12.18
Options Number Exercisable	303,564
Options Exercisable Weighted Average Exercise Price	$ 18.29
Range 1
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 5.20
Range of Exercise Prices, upper limit	$ 8.40
Options Number Outstanding	192,601
Options Outstanding Weighted Average Remaining Contractual Life (Years)	8 years 8 months 27 days
Options Outstanding Weighted Average Exercise Price	$ 6.57
Options Number Exercisable	50,148
Options Exercisable Weighted Average Exercise Price	$ 7.73
Range 2
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 8.41
Range of Exercise Prices, upper limit	$ 8.80
Options Number Outstanding	266,500
Options Outstanding Weighted Average Remaining Contractual Life (Years)	9 years 5 months 12 days
Options Outstanding Weighted Average Exercise Price	$ 8.80
Options Number Exercisable	583
Options Exercisable Weighted Average Exercise Price	$ 8.80
Range 3
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 8.81
Range of Exercise Prices, upper limit	$ 12.00
Options Number Outstanding	254,815
Options Outstanding Weighted Average Remaining Contractual Life (Years)	8 years 2 months 9 days
Options Outstanding Weighted Average Exercise Price	$ 11.20
Options Number Exercisable	97,682
Options Exercisable Weighted Average Exercise Price	$ 11.63
Range 4
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 12.01
Range of Exercise Prices, upper limit	$ 36.90
Options Number Outstanding	182,258
Options Outstanding Weighted Average Remaining Contractual Life (Years)	4 years 11 days
Options Outstanding Weighted Average Exercise Price	$ 22.02
Options Number Exercisable	140,264
Options Exercisable Weighted Average Exercise Price	$ 24.28
Range 5
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 36.91
Range of Exercise Prices, upper limit	$ 43.40
Options Number Outstanding	14,887
Options Outstanding Weighted Average Remaining Contractual Life (Years)	2 years 3 months 26 days
Options Outstanding Weighted Average Exercise Price	$ 41.49
Options Number Exercisable	14,887
Options Exercisable Weighted Average Exercise Price	$ 41.49