Stock-Based Compensation (Summary of Option Activity) (Details) - $ / shares	3 Months Ended	6 Months Ended
	Mar. 31, 2015	Jun. 30, 2015
2005 Plan [Member]
Stock Options
Outstanding at January 1, 2015	16,928,098	16,928,098
Granted		22,500
Exercised		(877,910)
Canceled		(153,375)
Outstanding at June 30, 2015		15,919,313
Shares exercisable at June 30, 2015		8,320,563
Weighted-Average Exercise Price
Outstanding at January 1, 2015	$ 3.24	$ 3.24
Granted		6.70
Exercised		2.24
Canceled		3.92
Outstanding at June 30, 2015		3.29
Shares exercisable at June 30, 2015		$ 2.51
1995 Plan [Member]
Stock Options
Outstanding at January 1, 2015	35,000	35,000
Granted		0
Exercised		(35,000)
Canceled		0
Outstanding at June 30, 2015		0
Shares exercisable at June 30, 2015		0
Weighted-Average Exercise Price
Outstanding at January 1, 2015	$ 2.21	$ 2.21
Granted		0
Exercised		2.21
Canceled		0
Outstanding at June 30, 2015		0
Shares exercisable at June 30, 2015		$ 0
2015 Plan [Member]
Stock Options
Outstanding at January 1, 2015	0	0
Granted	7,014,441	7,369,441
Exercised		0
Canceled		(55,500)
Outstanding at June 30, 2015		7,313,941
Shares exercisable at June 30, 2015		0
Shares available for grant at June 30, 2015		17,686,059
Weighted-Average Exercise Price
Outstanding at January 1, 2015	$ 0	$ 0
Granted	$ 8.94	8.97
Exercised		0
Canceled		8.94
Outstanding at June 30, 2015		8.97
Shares exercisable at June 30, 2015		$ 0