Stock-based Activity (Tables)

6 Months Ended

12 Months Ended

Jun. 30, 2016

Dec. 31, 2015

Stock-based Activity Tables

Stock-based Compensation

	Three Months Ended			Three Months Ended			Six Months Ended			Six Months Ended
	June 30,			June 30,			June 30,			June 30,
	2016			2015			2016			2015
Research and development		$	284,057		$	284,125		$	587,681		$	325,701
General and administrative			673,506			1,104,883			1,903,770			1,146,079
Total stock-based compensation expense		$	957,563		$	1,389,008		$	2,491,451		$	1,471,780

	Years Ended December 31,
	2015		2014
Research and development	$	929,633	$	163,019
General and administrative		3,534,062		441,957
Total share-based compensation expense	$	4,463,695	$	604,976

Stock-based Award Activity

	Options Outstanding			Weighted-Average Exercise Price
Outstanding at December 31, 2015		3,243,041		$	2.36
Granted		1,655,500			0.73
Exercised		—			—
Forfeited/cancelled/expired		(219,449	)		2.30
Outstanding and expected to vest at June 30, 2016		4,679,092		$	1.90
Vested and exercisable at June 30, 2016		1,005,213		$	2.54

Restricted stock grants

	Shares			Weighted-Average Grant-Date Fair Value
Nonvested at December 31, 2015		2,300,850		$	2.28
Granted		—			—
Vested		(726,952	)		2.30
Forfeited		—			—
Nonvested at June 30, 2015		1,573,898		$	2.28

Common stock reserved for future issuance

Common stock reserved for conversion of preferred stock	20,662,100
Common stock reserved for exercise of warrants	8,876,336
Common stock options outstanding	4,679,092
Authorized for future grant or issuance under the Stock Plan	1,521,038
Unvested restricted stock	1,573,898
Total	37,312,464

Common stock reserved for conversion of preferred stock and warrants	29,692,068
Common stock options outstanding	3,243,041
Authorized for future grant or issuance under the Stock Plan	2,970,012
Unvested restricted stock	2,300,850
Total	38,205,971