Net loss per common stock (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Schedule of Computation of Basic and Diluted Net Loss Per Common Stock

The detail of the computation of basic and diluted net loss per common stock is as follows:

	YEARS ENDED DECEMBER 31,
	2016			2015			2014
Numerator
Net loss	$	(37,002	)	$	(21,860	)	$	(24,027	)
Accretion for liquidation preference on preferred stock		—			—			(1,133	)
Accretion for share issuance costs on preferred stock		—			—			(20	)
Tax expense on preferred stock		—			—			(100	)
Reversal of tax payable on preferred stock due to conversion of preferred stock		—			—			1,898
Extinguishment of remaining share issuance costs due to conversion of preferred stock		—			—			(439	)
Total loss attributable to common stockholders	$	(37,002	)	$	(21,860	)	$	(23,821	)
Denominator
Weighted average number of shares used to compute basic and diluted net loss per common stock		18,893,515			12,637,839			8,667,387
Net loss per common stock attributable to common stockholders—basic and diluted	$	(1.96	)	$	(1.73	)	$	(2.75	)

Schedule of Antidilutive Securities Excluded from Computation of Basic and Diluted Net Loss Per Share

The following have been excluded from the computation of basic and diluted net loss per common stock as their effect would have been antidilutive:

	DECEMBER 31, 2016		DECEMBER 31, 2015		DECEMBER 31, 2014
Outstanding stock options		1,378,352		865,457		824,608
Common stock warrants		—		11,363		11,363
Total		1,378,352		876,820		835,971