Stock Plans and Stock-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 1.8
Weighted-average period	3 years 3 months 18 days
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares authorized to be issued under plan	7,557,567
Fiscal year over which number of shares reserved for issuance will increase, starting year	2013
Fiscal year over which number of shares reserved for issuance will increase, ending year	2022
Vesting period	4 years
Vesting period expires	10 years
2012 Equity Incentive Plan | Common stock shares outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares authorized to be issued under plan	4,000,000
2012 Equity Incentive Plan | 2011 stock plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares authorized to be issued under plan	3,800,000
2012 Equity Incentive Plan | Equity Incentive Plan that will be increased automatically on the first business day of each fiscal year, Scenario 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of increase in number of shares reserved for issuance	5.00%
2012 Equity Incentive Plan | Equity Incentive Plan that will be increased automatically on the first business day of each fiscal year, Scenario 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of increase in number of shares reserved for issuance	3,000,000