Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Allowances for doubtful accounts	$ 9	$ 9
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	33,943,787	33,619,766
Common stock, shares outstanding	28,355,624	28,637,022
Treasury stock, shares	5,588,163	4,982,744