The amount of cash consideration paid under collaborative arrangement.

No definition available.

Name:	acrs_CollaborativeArrangementCashConsideration
Namespace Prefix:	acrs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The portion of cash consideration paid into escrow under collaborative arrangement.

+ References

No definition available.

+ Details

Name:	acrs_CollaborativeArrangementPortionOfCashConsiderationPaidIntoEscrow
Namespace Prefix:	acrs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The portion of consideration payable at closing under collaborative arrangement.

+ References

No definition available.

+ Details

Name:	acrs_CollaborativeArrangementPortionOfConsiderationPayableAtClosing
Namespace Prefix:	acrs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Period end book value of specified lot of inventory.

+ References

No definition available.

+ Details

Name:	acrs_ConsiderationForProductInventory
Namespace Prefix:	acrs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage fee of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

No definition available.

+ Details

Name:	acrs_DebtInstrumentFinalPaymentFeePercentage
Namespace Prefix:	acrs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The debt instrument number of consecutive monthly payments.

+ References

No definition available.

+ Details

Name:	acrs_DebtInstrumentNumberOfConsecutiveMonthlyPayments
Namespace Prefix:	acrs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the part redemption amount for debt instrument.

+ References

No definition available.

+ Details

Name:	acrs_DebtInstrumentPartRedemptionAmount
Namespace Prefix:	acrs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the part redemption period for debt instrument.

+ References

No definition available.

+ Details

Name:	acrs_DebtInstrumentPartRedemptionPeriod
Namespace Prefix:	acrs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage fee of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

No definition available.

+ Details

Name:	acrs_DebtInstrumentRedemptionFeePercentage
Namespace Prefix:	acrs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The period for payment of royalties from closing date of acquisition.

+ References

No definition available.

+ Details

Name:	acrs_PeriodForPaymentOfRoyaltiesFromClosingDateOfAcquisition
Namespace Prefix:	acrs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Future payments that could be paid upon achievement of certain milestones per agreement.

+ References

No definition available.

+ Details

Name:	acrs_PotentialMilestonesPayable
Namespace Prefix:	acrs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum amount of borrowing capacity under a line of credit that is available as of the balance sheet date for a specific purpose other than for financing goods acquired for inventory or imminent delivery to a customer.

+ References

No definition available.

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow for cost incurred directly with the issuance of an equity security.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3291-108585

+ Details

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

- Definition

The cash inflow from the additional capital contribution to the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585

+ Details

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

- Definition

Amount of cash inflow (outflow) from long-term debt wholly or partially secured by collateral. Excludes tax exempt secured debt.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

+ Details

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

- Definition

Per share or per unit amount of equity securities issued.

+ References

No definition available.

+ Details

Name:	us-gaap_SharesIssuedPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=acrs_PublicOfferingOctober2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=acrs_AssetPurchaseAgreementEncompassingWorldwideRightsToOxymetazolineHydrochlorideCreamPlusIntellectualPropertyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended
	Oct. 31, 2018	Oct. 17, 2018	Oct. 15, 2018	Aug. 31, 2017
Subsequent events
Underwriters' discounts and commissions				$ 5,176
Subsequent event \| Secured Debt
Subsequent events
Loan, maximum borrowing capacity			$ 65,000
Proceeds from secured debt	$ 30,000
Loan, capacity not available due to restrictions			$ 35,000
Loan, unused capacity fee percentage			1.00%
Number of consecutive monthly payments			24 months
Final payment fee percentage			5.75%
Part prepayment period			3 months
Subsequent event \| Minimum \| Secured Debt
Subsequent events
Annual interest rate			8.35%
Part prepayment amount			$ 2,000
Subsequent event \| Public Offering October 2018
Subsequent events
Number of shares issued		9,941,750
Issuance price (in dollars per share)		$ 10.75
Aggregate gross proceeds		$ 106,874
Underwriters' discounts and commissions		$ 6,412
Subsequent event \| Prepayment prior to the first anniversary of the Funding Date \| Secured Debt
Subsequent events
Prepayment fee percentage			3.00%
Subsequent event \| Prepayment between the first and second anniversaries of the Funding Date \| Secured Debt
Subsequent events
Prepayment fee percentage			2.00%
Subsequent event \| Prepayment after the second anniversary of the Funding Date but before October 1, 2023 \| Secured Debt
Subsequent events
Prepayment fee percentage			1.00%
Subsequent event \| London Interbank Offered Rate (LIBOR) \| Secured Debt
Subsequent events
Basis spread over LIBOR			6.25%
Subsequent event \| APA
Subsequent events
Period for payment of royalties			10 years
Subsequent event \| APA \| Scenario, Forecast
Subsequent events
Portion of consideration to be paid at closing			$ 58,500
Portion of cash consideration paid into escrow			6,500
Cash consideration			65,000
Consideration for product inventory			1,000
Potential milestones payable			$ 5,000