Revenues

Revenue Recognition

Revenues are recognized when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. The majority of our revenues are recognized over time as services are performed, with certain revenues, most significantly the revenue share we earn from our print textbook partners, being recognized at the point in time when print textbooks are shipped to students.

The following table sets forth our total net revenues for the periods shown disaggregated for our Chegg Services and Required Materials product lines (in thousands, except percentages):



	Three Months Ended March 31,				Change
	2019		2018		$		%
Chegg Services	$	75,292	$	56,277	$	19,015	34	%
Required Materials	22,117		20,672		1,445		7	%
Total net revenues	$	97,409	$	76,949	$	20,460	27	%

During the three months ended March 31, 2019, we recognized $12.4 million of revenues that were included in our deferred revenue balance as of December 31, 2018. During the three months ended March 31, 2019, there was an immaterial amount of revenues recognized from performance obligations satisfied in previous periods. The aggregate amount of unsatisfied performance obligations is approximately $29.0 million as of March 31, 2019, of which substantially all is expected to be recognized into revenues over the next year and the remainder within three years.

Contract Balances

The following table presents our accounts receivable, net and deferred revenue balances (in thousands, except percentages):



					Change
	March 31, 2019		December 31, 2018		$			%
Accounts receivable, net	$	8,870	$	12,733	$	(3,863	)	(30	)%
Deferred revenue	$	26,276	$	17,418	$	8,858		51	%

During the three months ended March 31, 2019, our accounts receivable, net balance decreased by $3.9 million, or 30%, primarily due to an improvement in cash collections. During the three months ended March 31, 2019, our deferred revenue balance increased by $8.9 million, or 51%, primarily due to increased bookings for our Chegg Study service and eTextbook rentals driven by the seasonality of our business as well as the deferred variable consideration. Our contract assets balance was immaterial as of March 31, 2019 and December 31, 2018.