8.	Basic and Diluted Net Loss Per Share

In connection with the TTR License Agreement completed on April 17, 2018, with Ionis, we made distributions to Ionis representing the consideration to be paid in cash provided to Ionis in excess of the carrying value of the related assets acquired. These distributions are treated as dividends to Ionis; therefore, we have applied the two-class method loss per share to reflect the allocation of these distributions to the participating Ionis common shares.

The two-class method is an earnings allocation formula that determines loss per share for each class of common stock and participating security according to dividends declared (or accumulated) and participation rights in undistributed earnings. For the purposes of calculating loss per share under the two-class method, we have allocated the net loss between the common stock owned by Ionis and common stock owned by others. Basic loss per share for the participating common shares is computed by dividing total available losses to common stock owned by Ionis and common stock owned by others, by their respective weighted-average of common shares outstanding during the requisite period.

The following table summarizes the distributable losses for the three and six months ended June 30, 2018 and 2017 (in thousands):

	Three Months Ended June 30,						Six Months Ended June 30,
	2018			2017			2018			2017
Net loss	$	(62,046	)	$	(20,359	)	$	(91,673	)	$	(84,214	)
Distribution to Ionis		(7,792	)		—			(7,792	)		—
Distributable losses	$	(69,838	)	$	(20,359	)	$	(99,465	)	$	(84,214	)

The following table summarizes the reconciliation of weighted-average shares outstanding used in the calculation of basic loss per share for the three and six months ended June 30, 2018 and 2017:

	Three Months Ended June 30,				Six Months Ended June 30,
Determination of shares:	2018		2017		2018		2017
Weighted-average preferred shares outstanding		—		28,884,540		—		28,884,540
Weighted-average common shares outstanding owned by Ionis		60,832,494		—		53,182,685		—
Weighted-average common shares outstanding owned by others		21,492,157		—		21,332,650		—
Total weighted-average shares outstanding		82,324,651		28,884,540		74,515,335		28,884,540

The following table summarizes the calculation of basic loss per share for the three and six months ended June 30, 2018 and 2017 (in thousands, except per share amounts):

	Three Months Ended June 30,						Six Months Ended June 30,
	2018			2017			2018			2017
Losses allocated to preferred shares	$	—		$	(20,359	)	$	—		$	(84,214	)
Weighted-average preferred shares outstanding		—			28,884,540			—			28,884,540
Basic loss per preferred share	$	—		$	(0.70	)	$	—		$	(2.92	)

Losses allocated to Ionis	$	(51,606	)	$	—		$	(70,990	)	$	—
Plus: Distribution to Ionis		7,792			—			7,792			—
Losses available to Ionis	$	(43,814	)		—			(63,198	)		—
Weighted-average common shares outstanding owned by Ionis		60,832,494			—			53,182,685			—
Basic loss per common share owned by Ionis	$	(0.72	)	$	—		$	(1.19	)	$	—

Losses allocated to common shares owned by others	$	(18,232	)	$	—		$	(28,475	)	$	—
Weighted-average common shares outstanding owned by others		21,492,157			—			21,332,650			—
Basic loss per common share owned by others	$	(0.85	)	$	—		$	(1.33	)	$	—

For the three and six months ended June 30, 2018 and 2017, we incurred a net loss; therefore, we did not include dilutive common equivalent shares in the computation of diluted net loss per share because the effect would have been anti-dilutive. Common stock from the following would have had an anti-dilutive effect on net loss per share:

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Options to purchase common stock;

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Unvested restricted stock units; and

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Employee Stock Purchase Plan, or ESPP.