Stockholders' Equity (Narrative) (Details) (USD $)	1 Months Ended			12 Months Ended				1 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended										12 Months Ended
	Nov. 30, 2012	May 31, 2012	Oct. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 19, 2006 Series D Preferred Stock [Member]	May 31, 2010 Chief Operating Officer [Member]	Dec. 31, 2008 Chief Operating Officer [Member]	Dec. 31, 2008 Chief Operating Officer [Member] Stock Option Exercise Price 1 [Member]	Dec. 31, 2008 Chief Operating Officer [Member] Stock Option Exercise Price 2 [Member]	May 31, 2010 Chief Operating Officer [Member] Stock Option Amendment [Member]	Dec. 31, 2008 Chief Operating Officer [Member] Before June 2, 2009 [Member]	Dec. 31, 2008 Chief Operating Officer [Member] Before June 2, 2010 [Member]	Dec. 31, 2008 Chief Operating Officer [Member] Before June 2, 2011 [Member]	Dec. 31, 2008 Chief Operating Officer [Member] Before June 2, 2012 [Member]	Dec. 31, 2008 Chief Operating Officer [Member] Before June 2, 2013 [Member]	Dec. 31, 2008 Chief Operating Officer [Member] Before June 2, 2014 [Member]	Dec. 31, 2012 Equity Incentive Plan 1995 [Member]	Dec. 31, 2012 Plan 2005 [Member]	Dec. 31, 2012 Director Plan 1995 [Member]	Dec. 31, 2012 Director Plan 2004 [Member]	Dec. 31, 2012 Employee Stock Purchase Plan [Member]	Dec. 31, 2012 RSUs [Member]	Dec. 31, 2011 RSUs [Member]	Dec. 31, 2012 Inventory [Member]	Dec. 31, 2011 Inventory [Member]	Dec. 31, 2010 Inventory [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance																			6,100,000	13,600,000	750,000	1,765,000	1,300,000
Shares available for future issuance																				4,167,000		184,000	505,821
Stock plan maximum percentage withheld by employee																							15.00%
Common stock shares that can be purchased																							1,000
Stock discount percentage																							85.00%
Stock-based compensation expenses recognized				$ 3,897,000	$ 3,108,000	$ 2,224,000																				$ 100,000	$ 100,000	$ 44,000
Shares included in option to purchase grant to CEO								750,000		600,000	300,000
Unvested stock options modified amendment								0.03
Shares included in option to purchase grant to CEO, exercise price										$ 2.49	$ 1.81
Shares included in option to purchase grant to CEO, fair market price per share													$ 4.50	$ 6.00	$ 8.00	$ 10.00	$ 12.00	$ 14.00
Shares included in option to purchase grant to CEO, shares													150,000	150,000	150,000	150,000	150,000	150,000
grant date fair value of options per share				$ 3.36	$ 2.79	$ 2.10				$ 1.70	$ 0.88													$ 6.49	$ 5.81
Risk-free interest rate										5.10%	3.88%	2.28%
Volatility factor of the market price of common stock										94.00%	89.14%	71.83%
Dividend yield				0.00%	0.00%	0.00%			0.00%			0.00%
Fair value assumption, expected term, in years									10 years			5 years 26 days
Common stock, option exercises, shares				1,270,000	2,288,000	730,000
Unrecognized compensation expense, net of forfeitures				5,000,000																				900,000
Unrecognized compensation expense, weighted-average remaining period for recognition, in years																								1 year 5 months 1 day
Share based compensation costs				400,000	400,000	300,000
Share based compensation expense related to performance-based options				36,000	200,000	400,000
Vesting percentage after one year																								25.00%
Intrinsic value of options at exercise				4,500,000	5,800,000	1,300,000
Estimated fair value of shares vested				4,100,000	3,300,000	1,900,000
Compensation expense weighted average period recognized				2 years 5 months 19 days
Cash from stock option exercise				3,400,000	6,200,000	1,400,000
Weighted average fair value of options granted				$ 3.36	$ 2.79	$ 2.10				$ 1.70	$ 0.88													$ 6.49	$ 5.81
Share repurchase program, approved increase	10,000,000	10,500,000
Share repurchase program, amount authorized	40,500,000		20,000,000
Stock repurchased and retired, shares				4,709,000	781,000
Stock repurchased and retired, value				24,836,000	3,495,000
Share repurchase program, remaining amount authorized				$ 12,400,000
Preferred stock par value				$ 0.001	$ 0.001		$ 0.001
Preferred stock redemption price per share							$ 25.00
Minimum percentage of company common stock being acquired for the rights to become exercisable							15.00%
Common stock purchase discount percentage in the even of certain business combinations							50.00%
Redemmed price per share authorized by the board prior to a group or person acquiring 15% of common stock							$ 0.001