Stockholders' Equity (Fair Value of Options at Date of Grant) (Details) - Stock options	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Assumptions used to estimate the fair value of options at date of grant
Risk-free interest rate, minimum (as a percent)	1.37%
Risk-free interest rate, maximum (as a percent)	1.67%
Expected volatility (as a percent)		50.00%
Minimum
Assumptions used to estimate the fair value of options at date of grant
Expected term	5 years 5 months 19 days
Maximum
Assumptions used to estimate the fair value of options at date of grant
Expected term	6 years 5 months 12 days