Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 25, 2019
Document And Entity Information [Abstract]
Entity Registrant Name	LA JOLLA PHARMACEUTICAL CO
Entity Central Index Key	0000920465
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Shell Company	false
Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		27,157,205