Stock-based compensation expense was allocated as follows:


	Years Ended December 31,
	2022		2021
	(in thousands)
Cost of revenues	$	481	$	291
Sales and marketing		596		408
Research and development		996		594
General and administrative		1,482		728
	$	3,555	$	2,021

For stock-based awards granted by the Company, stock-based compensation cost is measured at grant date based on the fair value of the award and is expensed over the requisite service period. Stock-based compensation capitalized as internally developed software was $113 and $87 for 2022 and 2021, respectively.

As of December 31, 2022, there was $51 of unrecognized compensation cost related to options, which is expected to be recognized over a weighted-average period of 0.5 years.

As of December 31, 2022, there was $3,600 of unrecognized compensation cost related to RSUs, which is expected to be recognized over a weighted-average period of 1.5 years. The Company uses the fair market value of the underlying common stock on the dates of grant to determine the fair value of RSUs.

The Company estimates the fair value of purchase rights under the 2013 ESPP using the Black-Scholes valuation model. The fair value of each purchase right under the 2013 ESPP is estimated on the date of grant using the Black-Scholes option valuation model and the straight-line attribution approach with assumptions substantially similar to those used for the valuation of stock option awards, with the exception of the expected life. The expected life is estimated to be six months, which is consistent with the purchase periods under the 2013 ESPP.