Financial Instruments and Fair Value Measurements (Schedules of Concentration of Risk) (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 25, 2020	Sep. 27, 2019	Sep. 25, 2020	Sep. 27, 2019	Dec. 27, 2019
Distributor Concentration Risk | Revenue from Contract with Customer Benchmark [Member] | CuraScript, Inc
Concentration Risk
Concentration Risk, Percentage	28.10%	31.10%	27.70%	30.20%
Distributor Concentration Risk | Accounts Receivable Attributable to Distributors | Amerisource Bergen Corporation [Member]
Concentration Risk
Concentration Risk, Percentage			26.50%		31.30%
Distributor Concentration Risk | Accounts Receivable Attributable to Distributors | McKesson Corporation [Member]
Concentration Risk
Concentration Risk, Percentage			18.10%		15.30%
Distributor Concentration Risk | Accounts Receivable Attributable to Distributors | CuraScript, Inc
Concentration Risk
Concentration Risk, Percentage			13.20%		12.10%
Product Concentration Risk | Net Sales Attributable to Products | Acthar
Concentration Risk
Concentration Risk, Percentage	27.90%	30.90%	27.90%	30.50%
Product Concentration Risk | Net Sales Attributable to Products | Inomax
Concentration Risk
Concentration Risk, Percentage	20.30%	18.40%	21.20%	18.10%
Product Concentration Risk | Net Sales Attributable to Products | Ofirmev
Concentration Risk
Concentration Risk, Percentage	12.70%	11.60%	10.50%	11.50%