Share-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share Based Compensation [Abstract]
Stock-based compensation expense under share based plans	$ 424,000	$ 346,000	$ 811,000	$ 838,000
Cash received from employee stock purchase plan	627,000	273,000	827,000	416,000
Unrecognized compensation expense	$ 2,200,000		$ 2,200,000
Expected weighted-average recognition period for unrecognized compensation expense			1 year 4 months 24 days