Summary of Significant Accounting Policies (Potentially Dilutive Securities) (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted net loss per common share	3,779,387	3,242,574
Options to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted net loss per common share	3,728,149	3,176,336
Warrants to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted net loss per common share	51,238	66,238