Stockholders' Equity - Employee Stock Purchase Plan (Narrative) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for issuance	3,496
Employee Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 81	$ 77
Employee stock purchase plan, maximum contribution rate	10.00%	10.00%
Employee stock purchase plan, percentage of per share purchase price, lesser of fair market value on offering date or purchase date	Lesser of 85%	Lesser of 85%
Shares available for issuance	943
Employee stock purchase plan, maximum annual contribution	25	25