Organization and Business - Reverse stock-split and Liquidity (Details)			9 Months Ended	12 Months Ended
	Oct. 04, 2018 USD ($) $ / shares shares	May 18, 2018	Sep. 30, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares
Reverse stock split ratio		0.0667
Accumulated deficit			$ (81,896,894)	$ (62,404,722)
Number of pre-funded warrants issued | shares			889,921	106,376
October 2018 Equity Financing | Subsequent event
Shares issued (in shares) | shares	11,575,001
Number of pre-funded warrants issued | shares	3,425,000
Purchase price of common stock | $ / shares	$ 0.60
Gross proceeds from issuance of common stock	$ 7,000,000
Purchase price of pre-funded warrants | $ / shares	$ 0.59
Gross proceeds from issuance of pre-funded warrants	$ 2,000,000
Actual cash received after deducting estimated fees and expenses	$ 8,300,000