Legal Matters	12 Months Ended
Dec. 31, 2012
Legal Matters [Abstract]
Legal Matters	(12) Legal Matters On or about December 6, 2001, Variagenics, Inc. was sued in a complaint filed in the United States District Court for the Southern District of New York naming it and certain of its officers and underwriters as defendants. The complaint purportedly was filed on behalf of persons purchasing Variagenics’ stock between July 21, 2000 and December 6, 2000, and alleged violations of certain sections of the Securities Act of 1933, as amended, and the Securities Exchange Act of 1934, as amended. The complaint alleged that, in connection with Variagenics’ July 21, 2000 initial public offering, or IPO, the defendants failed to disclose additional and excessive commissions purportedly solicited by and paid to the underwriter defendants in exchange for allocating shares of Variagenics’ stock to preferred customers and alleged agreements among the underwriter defendants and preferred customers tying the allocation of IPO shares to agreements to make additional aftermarket purchases at predetermined prices. ARCA was involved in this litigation as a result of Nuvelo’s merger with Variagenics in January 2003. On April 1, 2009 the parties entered into a settlement agreement. On October 5, 2009, the Court approved the settlement agreement. ARCA’s share of the settlement was approximately $385,000 and was funded by ARCA’s insurance carrier. Although the settlement was approved by the Court, it had been appealed by members of the class. On January 9, 2012 the appeal was dismissed by the Court and the suit was settled.

Legal Matters

12 Months Ended

Dec. 31, 2012

(12) Legal Matters

On or about December 6, 2001, Variagenics, Inc. was sued in a complaint filed in the United States District Court for the Southern District of New York naming it and certain of its officers and underwriters as defendants. The complaint purportedly was filed on behalf of persons purchasing Variagenics’ stock between July 21, 2000 and December 6, 2000, and alleged violations of certain sections of the Securities Act of 1933, as amended, and the Securities Exchange Act of 1934, as amended. The complaint alleged that, in connection with Variagenics’ July 21, 2000 initial public offering, or IPO, the defendants failed to disclose additional and excessive commissions purportedly solicited by and paid to the underwriter defendants in exchange for allocating shares of Variagenics’ stock to preferred customers and alleged agreements among the underwriter defendants and preferred customers tying the allocation of IPO shares to agreements to make additional aftermarket purchases at predetermined prices. ARCA was involved in this litigation as a result of Nuvelo’s merger with Variagenics in January 2003. On April 1, 2009 the parties entered into a settlement agreement. On October 5, 2009, the Court approved the settlement agreement. ARCA’s share of the settlement was approximately $385,000 and was funded by ARCA’s insurance carrier. Although the settlement was approved by the Court, it had been appealed by members of the class. On January 9, 2012 the appeal was dismissed by the Court and the suit was settled.