Stock Option Plans - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	6 Months Ended			0 Months Ended		6 Months Ended		0 Months Ended
	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Apr. 15, 2014 2006 Equity Incentive Plan [Member]	Dec. 26, 2006 2006 Equity Incentive Plan [Member]	Jun. 30, 2014 2006 Equity Incentive Plan [Member]	Dec. 31, 2013 2006 Equity Incentive Plan [Member]	Dec. 26, 2006 2006 Equity Incentive Plan [Member] Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted period		6 years	5 years 10 months 24 days						10 years
Stock options granted description							Options under the 2006 Plan could be granted for periods of up to 10 years and at prices no less than 100% of the estimated fair value of the shares on the date of grant as determined by the board of directors, provided, however, that the exercise price of an ISO and NSO granted to a 10% shareholder could not be less than 110% of the estimated fair value of the shares on the date of grant.
Stock options granted to employees and non-employees vesting period						4 years
Common stock shares authorized for issuance							5,455,875	4,311,875
Common stock shares available for future grants		15,718,758		7,857,948			761,600	600,000
Increase in authorized shares available for future grants					1,144,000
Weighted-average fair values of options granted		$ 4.02
Unrecognized stock-based compensation expense related to employees' awards		$ 3.7
Unrecognized stock-based compensation, weighted-average period	2 years 8 months 12 days