pre_text: ADVANCED ENERGY INDUSTRIES, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – (continued) (in thousands, except per share amounts) NOTE 9. ACCOUNTS AND OTHER RECEIVABLE Accounts and other receivable are recorded at net realizable value. Components of accounts and other receivable, net of reserves, are as follows: Amounts billed, net consist of amounts that have been invoiced to our customers in accordance with terms and conditions, and are shown net of an allowance for doubtful accounts. These receivables are all short term in nature and do not include any financing components. Unbilled receivables consist of amounts where we have satisfied our contractual obligations related to inventory stocking contracts with customers. Such amounts are typically invoiced to the customer upon their consumption of the inventory managed under the stocking contracts. We anticipate that substantially all unbilled receivables will be invoiced and collected over the next twelve months. These contracts do not include any financing components.
table: December 31, 2019 December 31, 2018
table: Amounts billed, net $227,528 $80,709
table: Unbilled receivables 19,036 19,733
table: Total receivables, net $246,564 $100,442
question: Analyse this data from a financial earnings document. What was the change in unbilled receivables between 2018 and 2019?