10.

Preferred and Common Stock Warrants

As of March 31, 2019, the Company’s outstanding warrants to purchase shares of common stock consisted of the following:


Issuance Date	Number of Shares of Common Stock Issuable		Exercise Price		Classification		Expiration Date
August 14, 2015		81,228	$	21.78		Equity		August 14, 2020
August 21, 2015		69,603	$	21.78		Equity		August 21, 2020
October 25, 2016		5,155	$	19.78		Equity		October 24, 2026
November 1, 2017		130,609	$	19.78		Equity		October 31, 2020
November 17, 2017		8,442	$	19.78		Equity		November 16, 2020
December 4, 2017		5,661	$	19.78		Equity		December 3, 2020
December 28, 2017		6,925	$	19.78		Equity		December 27, 2020
December 28, 2017		115,916	$	19.78		Equity		December 28, 2027
September 12, 2018		25,275	$	19.78		Equity		September 12, 2021
September 12, 2018		20,220	$	19.78		Equity		September 12, 2028
October 19, 2018		20,016	$	19.78		Equity		October 19, 2028
December 11, 2018		5,004	$	19.80		Equity		October 19, 2028

		494,054

As of December 31, 2018, the Company’s outstanding warrants to purchase shares of preferred stock (which converted into warrants to purchase common stock upon close of the Merger) consisted of the following (not adjusted for the Reverse Stock Split or Exchange Ratio):

December 31, 2018

Warrant Name

Issuance Date

Number of
Shares of
Preferred
Stock Issuable

Exercise
Price

Exercisable
for

Classification

Expiration Date

Series A warrants

August 14, 2015

854,785

2.07

Series A

Liability

August 14, 2020

Series A warrants

August 21, 2015

732,453

2.07

Series A

Liability

August 21, 2020

SVB warrants

October 25, 2016

54,256

1.88

Series A

Liability

October 24, 2026

Series B warrants

November 1, 2017

1,374,435

1.88

Series B

Liability

October 31, 2020

Series B warrants

November 17, 2017

88,845

1.88

Series B

Liability

November 16, 2020

Series B warrants

December 4, 2017

59,576

1.88

Series B

Liability

December 3, 2020

Series B warrants

December 28, 2017

72,875

1.88

Series B

Liability

December 27, 2020

Series B warrants

December 28, 2017

1,219,815

1.88

Series B

Liability

December 28, 2027

Series B warrants

September 12, 2018

265,957

1.88

Series B

Liability

September 12, 2021

Series B warrants

September 12, 2018

212,765

1.88

Series B

Liability

September 12, 2028

Series B warrants

October 19, 2018

210,638

1.88

Series B

Liability

October 19, 2028

5,146,400

Prior to the Merger, the Company classified its preferred stock warrants as a liability on its consolidated balance sheet because the warrants are freestanding financial instruments that may have required the Company to transfer assets upon exercise. The liability associated with each of these warrants was initially recorded at fair value upon the issuance date of each warrant and is subsequently remeasured to fair value as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. Upon the closing of the Merger with Arsanis (see Note 1), pursuant to the Merger Agreement, all of the outstanding X4 preferred stock was converted to Arsanis common stock and the X4 preferred stock warrants converted to warrants for the purchase of Arsanis common stock. The Company assessed the features of the warrants and determined that they qualify for classification as permanent equity upon the closing of the Merger. Accordingly, the Company remeasured the warrants to fair value upon the closing of the Merger, which was $5,235 at March 13, 2019, with $288 of expense recorded during the three months ended March 31, 2019. Upon the closing of the Merger, the warrant liability was reclassified to additional paid-in capital.