Stockholders' Equity - Summary of Warrant Activity (Details)	12 Months Ended
	Dec. 31, 2015 $ / shares shares	Dec. 31, 2014 $ / shares shares	Dec. 31, 2013 $ / shares shares
Warrants Outstanding
Beginning balance (in shares) | shares	969,549	1,107,549	1,305,638
Warrants issued (in shares) | shares		147,000	2,549
Warrants expired (in shares) | shares	(205,000)	(285,000)	(200,638)
Warrants exercised (in shares) | shares	(638,189)
Warrants canceled/forfeited (in shares) | shares	(112,110)
Ending balance (in shares) | shares	14,250	969,549	1,107,549
Weighted Average Exercise Price During Period
Beginning balance (in dollars per share) | $ / shares	4.61	4.41	7.60
Warrants issued (in dollars per share) | $ / shares		4.65	3.49
Warrants expired (in dollars per share) | $ / shares	4.20	3.87	19.70
Warrants exercised (in dollars per share) | $ / shares	4.58
Warrants canceled/forfeited (in dollars per share) | $ / shares	5.54
Ending balance (in dollars per share) | $ / shares	4.30	4.61	4.41