Total stock-based compensation expense was $8,761, $5,528, $25,390 and $14,951 for the three months ended September 30, 2019 and 2018 and for the nine months ended September 30, 2019 and 2018, respectively. The following two tables show stock compensation expense by award type and where the stock compensation expense is recorded in the Company’s Unaudited Condensed Consolidated Income Statements:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Options	$	35	$	63	$	130	$	192
RSUs		8,726		5,465		25,260		14,759
Total stock-based compensation expense	$	8,761	$	5,528	$	25,390	$	14,951

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Cost of revenue	$	92	$	83	$	268	$	264
Sales and marketing expense		2,520		1,216		7,392		3,762
Product, technology, and development expense		3,938		2,584		11,118		6,903
General and administrative expense		2,211		1,645		6,612		4,022
Total stock-based compensation expense	$	8,761	$	5,528	$	25,390	$	14,951

Excluded from stock-based compensation expense is $324, $89, $950, and $299 of capitalized website development and internal-use software costs for the three months ended September 30, 2019 and 2018 and for the nine months ended September 30, 2019 and 2018, respectively.

During the three months ended September 30, 2019 and 2018 and nine months ended September 30, 2019 and 2018, the Company withheld 120,943, 93,933, 345,114, and 565,403 shares of Class A common stock, respectively, to satisfy employee tax withholding requirements and option costs due to net share settlements. The shares withheld remain in the authorized, but unissued pool under the Company’s Omnibus Equity Compensation Plan and can be reissued by the Company. Total payments for the employees’ tax obligations to the taxing authorities and for option costs due to net share settlements were $4,192, $4,379, $12,783, and $21,867 for the three months ended September 30, 2019 and 2018 and for the nine months ended September 30, 2019 and 2018, respectively, and are reflected as a financing activity within the Unaudited Condensed Consolidated Statements of Cash Flows.