Net Loss Per Share Attributable to Common Stockholders

The Company calculates basic and diluted net loss per share attributable to common stockholders in conformity with the two-class method required for companies with participating securities. The Company considers all series of convertible preferred stock issued and outstanding prior to the IPO to be participating securities. Under the two-class method, the net loss attributable to common stockholders is not allocated to the convertible preferred stock as the holders of convertible preferred stock issued and outstanding prior to the IPO do not have a contractual obligation to share in losses.

The diluted net loss per share attributable to common stockholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. For purposes of this calculation, options to purchase common stock, common stock warrants and securities such as convertible preferred stock and convertible preferred stock warrants that were issued and outstanding before the Company’s IPO, are considered common stock equivalents but have been excluded from the calculation of diluted net loss per share attributable to common stockholders as their effect is antidilutive. Basic and diluted net loss per common share was the same for each period presented, as the inclusion of all potential common shares outstanding would have been antidilutive.



(in thousands, except share and per share amounts)	Three Months Ended
(in thousands, except share and per share amounts)	March 30, 2019			March 31, 2018
Numerator:
Net loss attributable to common stockholders	$	(6,649	)	$	(5,696	)
Denominator:
Weighted average common shares outstanding—basic	6,974,301			5,793,801
Dilutive effect of stock equivalents resulting from stock options, common stock warrants, preferred stock warrants and convertible preferred stock (as converted)	—			—
Weighted average common shares outstanding—diluted	6,974,301			5,793,801
Net loss per common share—basic and diluted	$	(0.95	)	$	(0.98	)

The following weighted-average outstanding shares of common stock equivalents were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because the impact of including them would have been antidilutive:



	March 30, 2019	March 31, 2018
Convertible preferred stock (as converted)	41,562,111	39,474,156
Preferred stock warrants (as converted to common stock warrants and subsequently exercised)	160,767	160,767
Common stock warrants (as exercised)	60,002	—
Total	41,782,880	39,634,923