XML 20 R22.htm IDEA: XBRL DOCUMENT v2.4.1.9
Common stock - Narrative (Details) (USD $)
1 Months Ended 3 Months Ended 1 Months Ended
Mar. 31, 2014
Mar. 31, 2015
Apr. 30, 2014
Mar. 31, 2014
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Common stock, shares authorized   100,000,000us-gaap_CommonStockSharesAuthorized     61,000,000us-gaap_CommonStockSharesAuthorized
Common stock, par value (in usd per share)   $ 0.0001us-gaap_CommonStockParOrStatedValuePerShare     $ 0.0001us-gaap_CommonStockParOrStatedValuePerShare
Proceeds from sale of restricted common stock to founders $ 1,950flks_ProceedsFromSaleOfRestrictedCommonStock $ 0flks_ProceedsFromSaleOfRestrictedCommonStock      
Restricted common stock, vesting period   4 years      
Shares exercised   37,064us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised      
Shares exercised, weighted-average exercise price (in usd per share)   $ 10.79us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice      
Proceeds from early exercise of stock options 0us-gaap_ProceedsFromStockOptionsExercised 400,000us-gaap_ProceedsFromStockOptionsExercised      
Unvested restricted common stock sold to founders          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Restricted common stock, shares sold     867,314us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
4,553,415us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
 
Restricted common stock, price per share (in usd per share) $ 0.0004us-gaap_SaleOfStockPricePerShare
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
    $ 0.0004us-gaap_SaleOfStockPricePerShare
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
 
Proceeds from sale of restricted common stock to founders       $ 1,950flks_ProceedsFromSaleOfRestrictedCommonStock
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
 
Restricted common stock, repurchase period   90 days      
Restricted common stock, repurchase price (in usd per share)   $ 0.0004us-gaap_TreasuryStockAcquiredAverageCostPerShare
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
     
Restricted common stock, shares outstanding   2,456,227us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
     
Employee stock option          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares exercised   37,064us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
     
Shares exercised, weighted-average exercise price (in usd per share)   $ 10.79us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
     
Vests upon issuance | Unvested restricted common stock sold to founders          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Restricted common stock, percent vested   25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_VestingAxis
= us-gaap_ShareBasedCompensationAwardTrancheOneMember
     
Vests ratably over four years | Unvested restricted common stock sold to founders          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Restricted common stock, percent vested   75.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_VestingAxis
= us-gaap_ShareBasedCompensationAwardTrancheTwoMember
     
Restricted common stock, vesting period   4 years