Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended			3 Months Ended	6 Months Ended			12 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2014 Employees and Members of Board of Directors [Member]	Jun. 30, 2014 Employees and Members of Board of Directors [Member]	Jun. 30, 2014 Nonemployee Consultants [Member]	Jun. 30, 2014 2014 Equity Incentive Plan [Member]	Dec. 31, 2013 2014 Equity Incentive Plan [Member]	Jun. 30, 2014 2014 Equity Incentive Plan [Member] Maximum [Member]	Jun. 30, 2014 2004 Stock Incentive Plan [Member]	Dec. 31, 2013 2004 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options granted	227,000	0	614,000	0					0
Term of stock options granted											10 years
Share-based compensation arrangement by share-based payment award, number of shares authorized									1,600,000		30,000,000
Annual increase in number of shares reserved for issuance as a percentage of shares of capital stock outstanding through January 1, 2024										3.00%
Options outstanding	1,058,160		1,058,160		490,160								490,160
Weighted average exercise price of options	$ 7.62		$ 7.62		$ 1.34								$ 1.34
Number of shares available for future issuance												0	757,799
Fair value of options granted						$ 8.53	$ 7.55	$ 13.70