Commitments and Contingencies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Commitments And Contingencies [Line Items]
Lease expiration term	The Company leases office and laboratory space under two non-cancelable operating leases in Tucson, Arizona.
Lease extension term, in years	5 years
Expected increase in lease rent	$ 804,000
Leasehold improvements		$ 710,000
Monthly accreted lease term as reduction of rent expense	11,833
Rent expense and common area maintenance costs under operating leases	570,979	561,293
Discretionary contributions company may make	0	0
Computer Equipment
Commitments And Contingencies [Line Items]
Capital lease commitments	$ 83,000
Computer Equipment | Minimum
Commitments And Contingencies [Line Items]
Capital lease commitment period	36 months
Computer Equipment | Maximum
Commitments And Contingencies [Line Items]
Capital lease commitment period	48 months
Capitalized Leasehold Improvements
Commitments And Contingencies [Line Items]
Depreciation	$ 142,000	$ 130,167