Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Computation of Basic and Diluted Net Loss Per Share

The following table sets forth the computation of basic and diluted net loss per share (in thousands, except share and per‑share data):

	Year Ended December 31,
	2019			2018			2017
Numerator:
Net loss attributable to common stockholders	$	(55,350	)	$	(65,336	)	$	(65,321	)
Denominator:
Weighted‑average common shares and pre-funded warrants outstanding—basic and diluted	45,548,511			22,389,286			20,425,050
Net loss per share attributable to common stockholders —basic and diluted	$	(1.22	)	$	(2.92	)	$	(3.20	)

Schedule of Potential Common Shares Issuable Upon Conversion of Warrants

Potential dilutive common share equivalents consist of the following:

	Year Ended December 31,
	2019	2018	2017
Stock options to purchase common stock	6,796,669	4,093,979	2,657,187
Unvested restricted stock units	181,250	175,000	—
Stock warrants to purchase common stock	23,084,120	95,619	176,432
Total	30,062,039	4,364,598	2,833,619