Revenue from Contracts with Customers - Rebates and Allowances (Details) $ in Thousands	12 Months Ended
Dec. 31, 2018 USD ($)
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance, January 1, 2018	$ 2,860
Provision related to current period revenues	13,202
Adjustments relating to prior period revenues	(361)
Payments or credits made during the period	(11,047)
Balance, December 31, 2018	$ 4,654

Contract With Customer, Liability, Adjustment To Prior Period Revenues

No definition available.

Name:	lnth_ContractWithCustomerLiabilityAdjustmentToPriorPeriodRevenues
Namespace Prefix:	lnth_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Contract with Customer, Liability, Payments or Credits Made During the Period

+ References

No definition available.

+ Details

Name:	lnth_ContractwithCustomerLiabilityPaymentsorCreditsMadeDuringthePeriod
Namespace Prefix:	lnth_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Contract with Customer, Liability, Provision Related to Current Period Revenues

+ References

No definition available.

+ Details

Name:	lnth_ContractwithCustomerLiabilityProvisionRelatedtoCurrentPeriodRevenues
Namespace Prefix:	lnth_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 55
-Paragraph 27
-URI http://asc.fasb.org/extlink&oid=108792157&loc=SL49130611-203046-203046

+ Details

Name:	us-gaap_ContractWithCustomerRefundLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant