Commitments and Contingencies (Details)	3 Months Ended
Mar. 31, 2013 sqft
Commitments and Contingencies (Textual) [Abstract]
Office Space	1,954

Office area covered under operating lease agreement.

No definition available.

Name:	ljpc_OfficeAreaCoveredUnderOperatingLeaseAgreement
Namespace Prefix:	ljpc_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	duration