Related Party Transactions (Details)		1 Months Ended		3 Months Ended			9 Months Ended
	Jan. 06, 2018 shares	Jul. 31, 2019 USD ($)	Dec. 31, 2017 USD ($) shares	Sep. 30, 2019 USD ($) agreement	Sep. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Sep. 30, 2019 USD ($) director agreement	Sep. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Mar. 07, 2017 shares	Sep. 30, 2016 USD ($) shares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of exclusive channel collaboration agreements (agreement) | agreement				2			2
Related party payable				$ 72,000			$ 72,000			$ 100,000
Research and development expense				763,000	$ 1,541,000		3,306,000	$ 4,601,000
Common stock issued (shares) | shares	409,091
Warrants Issued With September 2016 Convertible Notes
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Warrants issued to purchase common stock (in shares) | shares												1,205,840
Affiliated Entity
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Expenses for work performed							100,000	400,000
Related party payable				100,000			100,000			$ 100,000
Research and development expense				$ 4,000	63,000		$ 44,000	(134,000)
Shareholder ownership percentage of related party in affiliate, more than				50.00%			50.00%
Shareholder ownership percentage				17.00%			17.00%
Affiliated Entity | 2017 Private Placement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Warrants issued to purchase common stock (in shares) | shares			545,456								259,176
Preferred stock, shares issued (shares) | shares											3,016
Common stock issued (shares) | shares			545,456
Affiliated Entity | Warrants Issued With September 2016 Convertible Notes
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Warrants issued to purchase common stock (in shares) | shares												450,835
Affiliated Entity | Convertible Debt
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Convertible debt principal												$ 6,762,500
Affiliated Entity | CCP Milestone Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty and milestone payments incurred		$ 3,800,000
Expenses for work performed							$ 3,800,000
Related party payable				$ 3,800,000			3,800,000
Affiliated Entity | Direct Expenses for Work Performed
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Expenses for work performed							10,000	100,000
Affiliated Entity | Pass-through Costs
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Expenses for work performed							$ 90,000	300,000
Affiliated Entity | 2012 ECC Dispute
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Related party payable			$ 700,000		$ 200,000			$ 200,000	$ 200,000
Research and development expense						$ 1,100,000			1,400,000
Due to related parties, reduction from prior period									$ 500,000
Director
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of directors (director) | director							2