Significant Accounting Policies, Fair Value of Stock-based Awards Valuation Assumptions (Details) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Employee Stock Purchase Plan ("ESPP") [Member]
Weighted average assumptions used for estimating fair value of stock-based awards [Abstract]
Risk free interest rate (in hundredths)	0.09%	0.05%	0.09%	0.05%
Expected term	6 months	6 months	6 months	6 months
Volatility (in hundredths)	39.25%	61.07%	39.25%	61.07%
Expected dividend (in hundredths)	0.00%	0.00%	0.00%	0.00%
Weighted average fair value (per share)	$ 0.38	$ 0.72	$ 0.38	$ 0.72
Stock Options [Member]
Weighted average assumptions used for estimating fair value of stock-based awards [Abstract]
Risk free interest rate (in hundredths)	1.10%	1.61%	1.23%	1.61%
Expected term	3 years 9 months	5 years 3 months 11 days	3 years 8 months 26 days	5 years 3 months 11 days
Volatility (in hundredths)	53.17%	57.30%	55.55%	57.30%
Expected dividend (in hundredths)	0.00%	0.00%	0.00%	0.00%
Weighted average fair value (per share)	$ 0.69	$ 1.20	$ 0.76	$ 1.20