Total stock-based compensation expense recognized in the accompanying condensed consolidated statements of operations for the three and nine months ended September 30, 2019 and 2018 was as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Stock-based compensation	$	1,640	$	1,562	$	5,312	$	5,715

During the three months ended September 30, 2019, the Company granted certain employees stock options to purchase an aggregate of 145,600 shares of common stock at a weighted average exercise price of $1.12 per share. The options vest over a four year period. The grant date fair value of these awards is $0.1 million with a weighted average grant date fair value of $0.66 per share, as determined using a Black-Scholes option pricing model.

During the nine months ended September 30, 2019, the Company granted certain employees stock options to purchase an aggregate of 5,478,903 shares of common stock at a weighted average exercise price of $1.32 per share. The options vest over a four year period. The grant date fair value of these awards is $6.0 million with a weighted average grant date fair value of $1.10 per share, as determined using a Black-Scholes option pricing model.

In the Condensed Statements of Stockholders’ Deficit and the Condensed Consolidated Statements of Cash Flows, the prior quarter’s stock-based compensation expense is inclusive of expenses associated with restricted stock unit awards in order to conform to the current quarter presentation.

As of September 30, 2019, there were $1.1 million and $11.1 million of unrecognized compensation expense related to restricted stock units and options, respectively, which vest over the vesting period except for certain options that are subject to performance conditions. The Company evaluates performance conditions as the probability that the performance conditions will be met and uses that information to estimate the date at which those performance conditions will be met in order to properly recognize stock-based compensation expense over the requisite service period.