Earnings Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Outstanding equity awards not included in the calculation of diluted net loss per share:
Shares issued: Options exercised	157,000	19,000	1,062,000	50,000
Share decreases: Shares repurchased for tax purposes	(3,000)	(4,000)	(20,000)	(151,000)
Stock options
Outstanding equity awards not included in the calculation of diluted net loss per share:
Number of antidilutive securities excluded from computation of earnings per share	2,794,413	4,457,057	10,245,392	9,167,615
Range of exercise prices, lower limit	$ 2.84	$ 1.74	$ 0.47	$ 1.26
Range of exercise prices, upper limit	$ 7.84	$ 16.36	$ 7.84	$ 16.36
Unvested restricted stock awards
Outstanding equity awards not included in the calculation of diluted net loss per share:
Number of antidilutive securities excluded from computation of earnings per share	0	112,977	8,050	279,415
Shares issued: Restricted stock awards granted	0	0	30,000	30,000
Share decreases: Restricted stock awards canceled	0	(2,000)	0	(25,000)
Warrant
Outstanding equity awards not included in the calculation of diluted net loss per share:
Number of antidilutive securities excluded from computation of earnings per share			1,602,489	1,602,489
Warrants, exercise price			$ 2.40	$ 2.40
2000ESPP
Outstanding equity awards not included in the calculation of diluted net loss per share:
Shares issued: Shares purchased under stock plan	0	351,000	266,000	809,000