Stock-Based Compensation - Schedule of Warrants Activity (Details)	6 Months Ended
	Jun. 30, 2019 $ / shares shares
Compensation Related Costs [Abstract]
Number of Stock Options Outstanding, beginning balance | shares	24,380,893
Number of Stock Options, Granted | shares
Number of Stock Options, Exercised | shares
Number of Stock Options, Expired or cancelled | shares	(2,164,682)
Number of Stock Options Outstanding, ending balance | shares	22,216,211
Weighted-Average Exercise Price, Outstanding, beginning balance | $ / shares	$ 1.05
Weighted-Average Exercise Price, Granted | $ / shares
Weighted-Average Exercise Price, Exercised | $ / shares
Weighted-Average Exercise Price, Expired or cancelled | $ / shares	2.72
Weighted-Average Exercise Price, Outstanding, ending balance | $ / shares	$ 0.88