Post-effective amendment to a registration statement that is not immediately effective upon filing

Pre Merger Warrants - Additional Information (Detail)

v2.4.1.9
Pre Merger Warrants - Additional Information (Detail) (USD $)
12 Months Ended 91 Months Ended
Sep. 30, 2014
Sep. 30, 2013
Sep. 30, 2013
Class of Warrant or Right [Line Items]      
Debt Conversion, Converted Instrument, Warrants or Options Issued     42us-gaap_DebtConversionConvertedInstrumentWarrantsOrOptionsIssued1
Preferred Stock, Par or Stated Value Per Share   0.01us-gaap_PreferredStockParOrStatedValuePerShare 0.01us-gaap_PreferredStockParOrStatedValuePerShare
Proceeds from Issuance or Sale of Equity     1,000,000us-gaap_ProceedsFromIssuanceOrSaleOfEquity
Minimum [Member]      
Class of Warrant or Right [Line Items]      
Percentage of principle balance of notes on conversion price of notes 6.00%arth_PercentageOfPrincipleBalanceOfNotesOnConversionPriceOfNotes
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
10.00%arth_PercentageOfPrincipleBalanceOfNotesOnConversionPriceOfNotes
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
10.00%arth_PercentageOfPrincipleBalanceOfNotesOnConversionPriceOfNotes
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Maximum [Member]      
Class of Warrant or Right [Line Items]      
Percentage of principle balance of notes on conversion price of notes 10.00%arth_PercentageOfPrincipleBalanceOfNotesOnConversionPriceOfNotes
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
  50.00%arth_PercentageOfPrincipleBalanceOfNotesOnConversionPriceOfNotes
/ us-gaap_RangeAxis
= us-gaap_MaximumMember