Commitments and Contingencies - Binding LOI (Details) - USD ($)						9 Months Ended	12 Months Ended
	Apr. 19, 2018	Mar. 31, 2018	Mar. 16, 2017	Nov. 10, 2016	Nov. 19, 2015	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Mar. 29, 2018	Jul. 31, 2016
Other Commitments [Line Items]
Stock issued during the period							$ 16,777,666
Market value of stock on measurement date (in dollars per share)									$ 19.18
Letter of Intent
Other Commitments [Line Items]
Stock newly-issued during the period (in shares)	37,866			14,327	14,327		0
Stock issued during the period			$ 83,300	$ 85,100	$ 120,300	$ 776,000	$ 0	$ 83,300
Additional stock issued during the period, upon milestones (in shares)		37,866	10,745		92,634
Shares issued (in shares)										3,582
Obligatory stock issuance period			1 year
Share price of stock issued (in dollars per share)			$ 7.75
Royalties received, threshold for share issuance		$ 2,000,000
Net product sales milestone one		30,000,000
Net product sales milestone two		40,000,000
Net product sales milestone three		55,000,000
Net product sales milestone four		$ 75,000,000
Common stock, value, to be issued									$ 726,000
Letter of Intent | Research and Development Expense
Other Commitments [Line Items]
Stock issued during the period						726,000
Letter of Intent | Other Expense
Other Commitments [Line Items]
Stock issued during the period						$ 50,000