Checkpoint Therapeutics, Inc. Quarterly report pursuant to Section 13 or 15(d)

Significant Accounting Policies (Details Textual) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Jan. 01, 2019	Mar. 31, 2019	Dec. 31, 2018	Mar. 17, 2015
Equity Method Investment, Annual Equity Fee, Percentage		2.50%		2.50%
Fortress Biotech, Inc [Member]
Equity Method Investment, Annual Equity Fee, Percentage	2.50%
Stock Issued During Period, Shares, New Issues	960,428	2,254
Research and Development Expense [Member]
Stock Issued During Period, Value, Issued for Services			$ 1.7