AVP-825 License Agreement (Details) - License Agreement Terms - USD ($)	3 Months Ended		9 Months Ended		57 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2018
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Aggregate cash payments received from license agreement					$ 70,000,000
Potential proceeds upon achievement of milestones					$ 50,000,000
Licensing revenues	$ 0	$ 0	$ 0	$ 0