AtriCure, Inc. — Director's Dealing 2011

Mar 16, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AtriCure, Inc. (ATRC)
CIK: 0001323885
Period of Report: 2011-03-14

Reporting Person: Discovery Group I, LLC (10% Owner)
Reporting Person: Murphy Michael R (10% Owner)
Reporting Person: Donoghue Daniel J (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-03-14	Common Stock	P	100	$9.55	Acquired	1574992	Indirect
2011-03-15	Common Stock	P	6065	$9.6868	Acquired	1581057	Indirect
2011-03-15	Common Stock	P	987	$9.6868	Acquired	367768	Indirect
2010-03-16	Common Stock	P	4942	$9.7306	Acquired	1585999	Indirect

Footnotes

F1: Discovery Group I, LLC is the General Partner of Discovery Equity Partners, L.P., which is a discretionary client of the reporting person,
that owns the reported securities. The reporting person disclaims beneficial ownership of the reported securities except to the extent of
its pecuniary interest therein.

F2: Discovery Group I, LLC is an investment manager for Pleiades Investment Partners - D, L.P., which is a discretionary client of the reporting
person, that owns the reported securities. The reporting person disclaims beneficial ownership of the reported securities except to the
extent of its pecuniary interest therein.

F3: This transaction was executed in multiple trades at prices ranging from $9.50 to $9.75. The price reported above reflects the weighted
average purchase price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of
the issuer full information regarding the number of shares and prices at which the transaction was effected

F4: This transaction was executed in multiple trades at prices ranging from $9.69 to $9.80. The price reported above reflects the weighted
average purchase price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of
the issuer full information regarding the number of shares and prices at which the transaction was effected