Commitments and Contingencies - Future Minimum Lease Payments Excluding Operating Costs (Details) $ in Thousands	Mar. 31, 2021 USD ($)
Leases [Abstract]
2021	$ 175
2022	181
2023	166
Total future minimum lease payments	522
Less: discount	(32)
Total lease liabilities	$ 490

Lessee operating lease liability payments excluding lease operating cost due.

No definition available.

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Namespace Prefix:	ljpc_
Data Type:	xbrli:monetaryItemType
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- Definition

Lessee operating lease liability payments excluding lease operating cost, undiscounted excess amount.

+ References

No definition available.

+ Details

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- Definition

Lessee operating lease liability payments excluding lease operating costs due next twelve months.

+ References

No definition available.

+ Details

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Namespace Prefix:	ljpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Lessee operating lease liability payments excluding lease operating costs due remainder of fiscal year.

+ References

No definition available.

+ Details

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- Definition

Lessee operating lease liability payments excluding lease operating costs due year two.

+ References

No definition available.

+ Details

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Namespace Prefix:	ljpc_
Data Type:	xbrli:monetaryItemType
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- References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977

+ Details

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Balance Type:	credit
Period Type:	instant