Stockholders' Equity (Fair Value of Options at Date of Grant) (Details) - Stock options - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value of options granted	$ 5.52	$ 4.40	$ 2.89
Assumptions used to estimate the fair value of options at date of grant
Risk-free interest rate, minimum (as a percent)	1.37%	1.66%	0.78%
Risk-free interest rate, maximum (as a percent)	1.77%	2.29%	1.61%
Expected volatility (as a percent)		50.00%	55.00%
Minimum
Assumptions used to estimate the fair value of options at date of grant
Expected term	5 years 5 months 19 days	5 years	5 years
Expected volatility (as a percent)	49.00%
Maximum
Assumptions used to estimate the fair value of options at date of grant
Expected term	6 years 5 months 12 days	7 years 3 months	7 years 3 months
Expected volatility (as a percent)	50.00%