REVENUE RECOGNITION AND RELATED ALLOWANCES - Allowances (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Accruals and allowances
Beginning balance	$ 100,328
Ending balance	80,722
Chargebacks
Accruals and allowances
Beginning balance	88,746	$ 49,882
Accruals/Adjustments	96,701	95,393
Credits Taken Against Reserve	(114,114)	(51,575)
Ending balance	71,333	93,700
Government Rebates
Accruals and allowances
Beginning balance	7,826	8,901
Accruals/Adjustments	4,656	3,567
Credits Taken Against Reserve	(3,810)	(4,438)
Ending balance	8,672	8,030
Returns
Accruals and allowances
Beginning balance	27,155	16,595
Accruals/Adjustments	4,811	5,937
Credits Taken Against Reserve	(3,022)	(4,918)
Ending balance	28,944	17,614
Administrative Fees and Other Rebates
Accruals and allowances
Beginning balance	8,906	8,281
Accruals/Adjustments	7,634	8,922
Credits Taken Against Reserve	(9,184)	(8,817)
Ending balance	7,356	8,386
Prompt Payment Discounts
Accruals and allowances
Beginning balance	3,839	2,549
Accruals/Adjustments	3,196	3,361
Credits Taken Against Reserve	(3,959)	(2,219)
Ending balance	$ 3,076	$ 3,691

No definition available.

Name:	srt_ValuationAndQualifyingAccountsDisclosureLineItems
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increase (decrease) in valuation and qualifying accounts and reserves from adjustment.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690

+ Details

Name:	us-gaap_ValuationAllowancesAndReservesAdjustments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of valuation and qualifying accounts and reserves.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column B))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column E))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690

+ Details

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

- Definition

Amount of decrease in valuation and qualifying accounts and reserves.

+ References

+ Details

Name:	us-gaap_ValuationAllowancesAndReservesDeductions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=anip_ChargebacksMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=anip_GovernmentRebatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=anip_AllowancesForSalesReturnsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=anip_AdministrativeFeesAndOtherRebatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=anip_ReservesForCashDiscountMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: