POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that each person whose signature
appears below hereby constitutes and appoints Jeffrey B. Steinberg
his true and lawful attorney-in-fact, with full power of substitution,
to sign any and all instruments, certificates and documents that may
be necessary, desirable or appropriate to be executed on behalf of
himself as an individual or in his capacity as a general partner of
any partnership, pursuant to section 13 and 16 of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), and any and
all regulations promulgated thereunder, and Rules 144, 144A and 145
under the Securities Act of 1933, as amended (the "Securities Act"),
and to file the same, with all exhibits thereto, and any other
documents in connection therewith, with the Securities and Exchange
Commission, and with any other entity when and if such is mandated
by the Exchange Act, by the Securities Act or by the By-laws of the
National Association of Securities Dealers, Inc., granting unto
said attorney-in-fact full power and authority to do and perform
each and every act and thing necessary, desirable or appropriate,
fully to all intents and purposes as he might or could do in person,
thereby ratifying and confirming all that said attorney-in-fact, or
his substitutes may lawfully do or cause to be done by virtue hereof.

IN WITNESS WHEREOF, this Power of Attorney has been signed as of the
20th day of December, 1996.

Signature:  /s/ James H. Cavanaugh

Print Name: 	James H. Cavanaugh

Signature:  /s/ John Littlechild

Print Name:	John Littlechild

Signature:  /s/ Harold Werner

Print Name:	Harold Werner

Signature:  /s/ William W. Crouse

Print Name:	William W. Crouse