ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Product Sales and Royalties (Details)	3 Months Ended
	Mar. 31, 2020
Product Sales and Royalties
Product return period prior to expiration	6 months
Period after expiration for accepting unsalable product (up to)	12 months
Cash discount	2.00%
Discount reimbursement period after filling of prescription subject to discount	1 month
Zipsor
Product Sales and Royalties
Product shelf-life	36 months
Minimum
Product Sales and Royalties
Collection period after delivery	1 month
Discount taken off period after the quarter in which product shipped to the customer	1 month
Period after the quarter in which prescription is filled for paying rebate	2 months
Contract with customer, managed care rebate liability, period after quarter in which prescription is filled	1 month
Contract with customer, Medicare Part D coverage gap rebate liability, period after quarter in which prescription is filled	2 months
Minimum \| NUCYNTA ER and NUCYNTA
Product Sales and Royalties
Product shelf-life	24 months
Minimum \| Gralise
Product Sales and Royalties
Product shelf-life	24 months
Minimum \| CAMBIA
Product Sales and Royalties
Product shelf-life	24 months
Minimum \| Lazanda
Product Sales and Royalties
Product shelf-life	24 months
Maximum
Product Sales and Royalties
Collection period after delivery	2 months
Product return period prior to expiration	6 months
Period after expiration for accepting unsalable product (up to)	12 months
Discount taken off period after the quarter in which product shipped to the customer	2 months
Period after the quarter in which prescription is filled for paying rebate	3 months
Contract with customer, managed care rebate liability, period after quarter in which prescription is filled	3 months
Contract with customer, Medicare Part D coverage gap rebate liability, period after quarter in which prescription is filled	3 months
Maximum \| NUCYNTA ER and NUCYNTA
Product Sales and Royalties
Product shelf-life	36 months
Maximum \| Gralise
Product Sales and Royalties
Product shelf-life	36 months
Maximum \| CAMBIA
Product Sales and Royalties
Product shelf-life	48 months
Maximum \| Lazanda
Product Sales and Royalties
Product shelf-life	36 months

Assertio Therapeutics, Inc 10-Q