License Agreements and Grants - Arizona Commerce Authority and R&D Refundable Tax Credit Program (Details)	1 Months Ended		3 Months Ended	9 Months Ended
	Jan. 31, 2018 USD ($)	Aug. 31, 2012 USD ($) job milestone	Sep. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)
Research and Development [Abstract]
Arizona Commerce Authority grant | $		$ 1,000,000.0
Number of installments | milestone		4
Qualified jobs created, milestone 1 | job		15
Qualified jobs created, milestone 2 | job		30
Qualified jobs created, milestone 3 | job		40
Qualified jobs created, milestone 4 | job		65
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue recognized | $	$ 1,000,000		$ 30,000	$ 65,000
Minimum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Capital investment milestone | $		$ 4,500,000.0
Grant related minimum annual wages | $		$ 63,000
Percent of company paid premiums		65.00%