4. Net loss per share

Basic net loss per common share is calculated by dividing the net loss by the weighted‑average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted‑average number of common shares and potentially dilutive securities outstanding for the period determined using the treasury‑stock and if‑converted methods. For purposes of the diluted net loss per share calculation, unvested restricted common stock, restricted stock units, stock options, and warrants are considered to be potentially dilutive securities, but are excluded from the calculation of diluted net loss per share because their effect would be anti‑dilutive and therefore basic and diluted net loss per share were the same for all periods presented.

The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because to do so would be anti‑dilutive (in common stock equivalent shares):


	September 30,
	2019	2018
Unvested restricted common stock and restricted stock units	422,336	376,949
Outstanding stock options	2,662,334	2,565,895
Outstanding warrants	10,000	76,041
Total	3,094,670	3,018,885

As of September 30, 2019 and 2018, the Company had an obligation to issue warrants to purchase an additional 93,341 shares of common stock to a vendor if a contract is terminated prior to a minimum purchase commitment being met. No amounts are presented in the table above for this obligation to issue a warrant as the issuance of the warrant is not considered probable.