Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F5,F1,F3,F4	Dec 10, 2015	P	32,211	$8.5902	A	2,048,598	I	Through Deerfield Partners, L.P.
Common Stock^F5,F1,F3,F4	Dec 10, 2015	P	40,997	$8.5902	A	2,607,307	I	Through Deerfield International Master Fund, L.P.
Common Stock^F1,F3,F4	Dec 10, 2015	P	29,902	$8.5902	A	1,006,744	I	Through Deerfield Special Situations Fund, L.P.
Common Stock^F2,F5,F3,F4	Dec 11, 2015	P	100,864	$8.6089	A	2,149,462	I	Through Deerfield Partners, L.P.
Common Stock^F2,F5,F3,F4	Dec 11, 2015	P	128,374	$8.6089	A	2,735,681	I	Through Deerfield International Master Fund, L.P.
Common Stock^F2,F3,F4	Dec 11, 2015	P	93,634	$8.6089	A	1,100,378	I	Through Deerfield Special Situations Fund, L.P.

Table II — derivative securities

No Table II lines on this filing.

Explanation of responses

F1The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $8.50 to $8.65, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in footnotes (1) and (2) of this Form 4.
F2The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $8.50 to $8.655, inclusive.
F3This Form 4 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt, L.P. is the general partner of Deerfield Special Situations Fund, L.P. ("DSS"), Deerfield Partners, L.P. ("DP") and Deerfield International Master Fund, L.P. ("DFIM," and together with DSS and DP, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt, L.P. and Deerfield Management Company, L.P.
F4In accordance with Instruction 4 (b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Funds is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.
F5This Amendment to the Form 4 filed with the Commission on December 11, 2015 (the "Original Filing") is being filed to correct an error, whereby (i) 40,997 shares of common stock purchased by DFIM were inadvertently reported as being purchased by DP, (ii) 32,211 shares of common stock purchased by DP were inadvertently reported as being purchased by DFIM. This amendment also corrects resulting errors in the number of shares of common stock beneficially owned by DP and DFIM following such transactions. The aggregate number of shares acquired by the Funds, as reflected in the Original Filing, remains unchanged.

Remarks

Jonathan Isler, Attorney-in-Fact: Power of Attorney, which is hereby incorporated by reference to Exhibit 24 to a Form 3 with regard to Avalanche Biotechnologies, Inc. filed with the Securities and Exchange Commission on July 30, 2014 by Deerfield Mgmt III, L.P., Deerfield Mgmt, L.P., Deerfield Management Company, L.P., Deerfield Special Situations Fund, L.P., Deerfield Special Situations International Master Fund, L.P., Deerfield Private Design Fund III, L.P. and James E. Flynn