Warrants (Tables)

12 Months Ended

Dec. 31, 2015

Warrants.

Schedule of additional information related to warrants

	Year ended December 31,
	2015		2014		2013
Weighted-average grant date fair value for warrants granted during the period	$	—	$	—	$	—
Total fair value of warrants vested during the period		—		—		—
Total intrinsic value of warrants exercised during the period		—		142,625		594,002