Stockholders' Equity - Warrants (Details) - 6 months ended Jun. 30, 2015	$ / shares shares
Warrants Outstanding
Outstanding at the beginning of the period (in shares) | shares	969,549
Exercised (in shares) | shares	(582,549)
Canceled/forfeited (in shares) | shares	(55,000)
Expired (in shares) | shares	(240,000)
Outstanding at the end of the period (in shares) | shares	92,000
Weighted Average Exercise Price During Period
Outstanding at the beginning of the period (dollars per share)	$ 4.61
Exercised (dollars per share)	4.30
Canceled/forfeited (dollars per share)	4.30
Expired (dollars per share)	5.34
Outstanding at the end of the period (dollars per share)	$ 4.86