Stock Options Outstanding and Vested and Exercisable (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	3,708,773
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	6 years 6 months
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 9.43
Options Vested, Number of Options Vested	2,324,788
Options Vested, Weighted Average Exercise Price Per Share	$ 6.33
$1.00 - $2.00
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Lower Limit	$ 1.00
Exercise Prices, Upper Limit	$ 2.00
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	14,042
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	1 year 1 month 6 days
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 1.34
Options Vested, Number of Options Vested	14,042
Options Vested, Weighted Average Exercise Price Per Share	$ 1.34
$3.30
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices	$ 3.30
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	381,521
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	2 years 4 months 24 days
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 3.30
Options Vested, Number of Options Vested	381,521
Options Vested, Weighted Average Exercise Price Per Share	$ 3.30
$3.6 - $4.10
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Lower Limit	$ 3.6
Exercise Prices, Upper Limit	$ 4.10
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	378,399
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	3 years 10 months 24 days
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 4.09
Options Vested, Number of Options Vested	378,399
Options Vested, Weighted Average Exercise Price Per Share	$ 4.09
$4.5 - $5.10
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Lower Limit	$ 4.5
Exercise Prices, Upper Limit	$ 5.10
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	463,189
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	3 years 7 months 6 days
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 5.02
Options Vested, Number of Options Vested	463,189
Options Vested, Weighted Average Exercise Price Per Share	$ 5.02
$5.30
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices	$ 5.30
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	152,750
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	4 years 6 months
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 5.30
Options Vested, Number of Options Vested	152,750
Options Vested, Weighted Average Exercise Price Per Share	$ 5.30
$7.00
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices	$ 7.00
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	449,244
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	8 years 1 month 6 days
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 7.00
Options Vested, Number of Options Vested	206,664
Options Vested, Weighted Average Exercise Price Per Share	$ 7.00
$8.50
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices	$ 8.50
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	416,921
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	7 years 2 months 12 days
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 8.50
Options Vested, Number of Options Vested	270,056
Options Vested, Weighted Average Exercise Price Per Share	$ 8.50
$9.00
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices	$ 9.00
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	379,318
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	6 years 4 months 24 days
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 9.00
Options Vested, Number of Options Vested	354,875
Options Vested, Weighted Average Exercise Price Per Share	$ 9.00
$9.5 - $10.90
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Lower Limit	$ 9.5
Exercise Prices, Upper Limit	$ 10.90
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	406,068
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	9 years 2 months 12 days
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 10.05
Options Vested, Number of Options Vested	26,693
Options Vested, Weighted Average Exercise Price Per Share	$ 9.75
$19.74 - $28.47
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Lower Limit	$ 19.74
Exercise Prices, Upper Limit	$ 28.47
Options Outstanding and Exercisable, Number of Options Outstanding and Exercisable	667,321
Options Outstanding and Exercisable, Weighted Average Remaining Contractual Life (Years)	9 years 7 months 6 days
Options Outstanding and Exercisable, Weighted Average Exercise Price per Share	$ 22.23
Options Vested, Number of Options Vested	76,599
Options Vested, Weighted Average Exercise Price Per Share	$ 20.25