Stock Based Compensation - Company's Options Outstanding (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding - Number of Shares	2,112,632
Options exercisable - Number of Shares	872,414
Exercise Price Range 0.32 -1.92 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Minimum	$ 0.32
Exercise Price, Maximum	$ 1.92
Options outstanding - Number of Shares	862,856
Options outstanding -Weighted- Average Remaining Contractual Life in Years	8 years 2 months 5 days
Options exercisable - Number of Shares	416,309
Options exercisable Weighted- Average Remaining Contractual Life in Years	8 years 1 month 17 days
Exercise Price Range 2.24 -3.84 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Minimum	$ 2.24
Exercise Price, Maximum	$ 3.84
Options outstanding - Number of Shares	457,740
Options outstanding -Weighted- Average Remaining Contractual Life in Years	6 years 5 months 23 days
Options exercisable - Number of Shares	369,142
Options exercisable Weighted- Average Remaining Contractual Life in Years	6 years 4 months 28 days
Exercise Price Range 5.12 - 6.72 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Minimum	$ 5.12
Exercise Price, Maximum	$ 6.72
Options outstanding - Number of Shares	418,030
Options outstanding -Weighted- Average Remaining Contractual Life in Years	8 years 4 months 6 days
Options exercisable - Number of Shares	85,309
Options exercisable Weighted- Average Remaining Contractual Life in Years	7 years 11 months 1 day
Exercise Price Range 8.96 - 12.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Minimum	$ 8.96
Exercise Price, Maximum	$ 12.50
Options outstanding - Number of Shares	374,006
Options outstanding -Weighted- Average Remaining Contractual Life in Years	9 years 8 months 23 days
Options exercisable - Number of Shares	1,654
Options exercisable Weighted- Average Remaining Contractual Life in Years	9 years 9 months 15 days