Summary of Activity Related to ESPP (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at beginning of period	$ 3	$ 8
Employee purchases	518	474	332
Cost of common stock issued	(518)	(479)	(324)
Balance at End of Period	$ 3	$ 3	$ 8