AtriCure, Inc. — Director's Dealing 2011

Mar 2, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AtriCure, Inc. (ATRC)
CIK: 0001323885
Period of Report: 2011-02-28

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

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-02-28	Common Stock	P	10234	$10.0753	Acquired	1503072	Indirect
2011-02-28	Common Stock	P	1666	$10.0753	Acquired	1758161	Indirect
2011-03-01	Common Stock	P	3560	$10.0898	Acquired	1506632	Indirect
2011-03-01	Common Stock	P	580	$10.0898	Acquired	1797561	Indirect
2011-03-02	Common Stock	P	35260	$10.1045	Acquired	1541892	Indirect
2011-03-02	Common Stock	P	5740	$10.1045	Acquired	261409	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 $10.02 to $10.10. 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 $10.07 to $10.10. 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

F5: This transaction was executed in multiple trades at prices ranging from $10.07 to $10.12. 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