Operating Leases: (Details) - USD ($)	6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019
Operating Leases:
Weighted average remaining lease term	9 years 6 months
Weighted average discount rate (as a percent)	5.50%
Rent expense	$ 597,400	$ 720,600
Maturities of operating lease liabilities:
2020	355,100
2021	723,100
2022	742,900
2023	763,300
2024	784,400
Thereafter	4,258,600
Total	7,627,400
Less imputed interest	(1,684,900)
Present value of lease liabilities	5,942,500
Operating lease liability
Operating lease liability, current	$ 400,000
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued Liabilities, Current
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flow outflow from operating leases	$ 348,600	$ 353,700