Product Sales - Over Time Under Topic 606, the Company recognizes revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration the Company expects to be entitled to in exchange for goods or services provided. Revenue associated with contracts with customers is recognized over time as the Company's performance creates or enhances customer controlled assets or creates or enhances an asset with no alternative use, which the Company has an enforceable right to receive compensation as defined under the contract for performance completed. To determine the amount of revenue to recognize over time, the Company recognizes revenue over the contract terms based on the output method. The Company applied the "as invoiced" practical expedient as the amount of consideration the Company has the right to invoice corresponds directly with the value of the Company's performance to date. As the output method is driven by units produced, the Company recognizes revenues based on the value transferred to the customer relative to the remaining value to be transferred. The Company also matches the costs associated with the units produced. If a contract is projected to result in a loss, the entire contract loss is recognized in the period when the loss was first determined and the amount of the loss updated in subsequent reporting periods. Revenue recognition also includes an amount related to a contract asset or contract liability. If the recognized revenue is greater than the amount billed to the customer, a contract asset is recorded in accounts receivable - unbilled. Conversely, if the amount billed to the customer is greater than the recognized revenue, a contract liability is recorded in customer deposits on uncompleted contracts. Changes in the job performance, job conditions and final contract settlements are factors that influence managements assessment of total contract value and therefore, profit and revenue recognition. A portion of the work the Company performs requires financial assurances in the form of performance and payment bonds or letters of credit at the time of execution of the contract. Some contracts include retention provisions of up to 10% which are generally withheld from each progress payment as retainage until the contract work has been completed and approved. Product Sales - Point in Time For certain product sales that do not meet the over time criteria, under Topic 606 the Company recognizes revenue when the product has been shipped to the destination in accordance with the terms outlined in the contract where a present obligation to pay exists as the customers have gained physical possession of the product. Accounts Receivable and Contract Balances The timing of when we bill our customers is generally dependent upon advance billing terms, milestone billings based on the completion of certain phases of the work, or when services are provided or products are shipped. Projects with performance obligations recognized over time that have costs and estimated earnings recognized to date in excess of cumulative billings, are reported on our Condensed Consolidated Balance Sheets as "Accounts receivable trade - unbilled" (i.e. contract assets). Projects with performance obligations recognized over time that have cumulative billings in excess of costs and estimate earnings recognized to date, are reported on our Condensed Consolidated Balance Sheets as "Customer deposits" (i.e. contract liabilities). Any uncollected billed amounts for our performance obligations recognized over time, including contract retentions, are recorded within accounts receivable trade - billed. At December 31, 2018 and December 31, 2017, accounts receivable included contract retentions (in thousands) of approximately $1,704 and $1,065, respectively. Our billed and unbilled revenue may be exposed to potential credit risk if our customers should encounter financial difficulties, and we maintain reserves for specifically-identified potential uncollectible receivables. At December 31, 2018 and December 31, 2017, our allowances for doubtful accounts (in thousands) were $214 and $208, respectively. Effect of Adopting ASC Topic 606 No adjustment to beginning 2018 retained earnings was recorded as a result of our adoption of Topic 606 due to no changes in the methods and/or timing of our revenue recognition for our uncompleted contracts. Further, the difference in our results for 2018 between application of the new standard on our contracts and what results would have been if such contracts had been reported using the accounting standards previously in effect, for such contracts, did not change. Sale to Customer with a Buy-Back Guarantee The Company entered into a buy-back agreement with one specific customer. Under this agreement, the Company guaranteed to buy-back product at a predetermined price at the end of the long-term project, subject to the condition of the product. Although the Company receives payment in full as the product is produced, we are required to account for these transactions as operating leases. The amount of sale proceeds equal to the buy-back obligation, included in "Deferred buy-back lease obligation" in the liabilities section of the consolidated balance sheet, is deferred until the buy-back is exercised or expired. The remaining sale proceeds are deferred in the same account and recognized on a straight-line basis over the usage period, such usage period commencing on delivery to the job-site and ending at the time the buy-back is exercised or expired. The Company capitalizes the cost of the product on the consolidated balance sheet shown in "Deferred buy-back lease asset, net", and depreciates the value, less residual value, to cost of leasing revenue in "Cost of goods sold" over the estimated useful life of the asset. In the case the customer does not exercise the buy-back option and retains ownership of the product at the end of the usage period, the guarantee buy-back liability and any deferred revenue balances related to the product are settled to revenue, and the net book value of the asset is expensed to cost of leasing revenue. If the customer exercises the buy-back guarantee option, the Company purchases the product back in the amount equal to the buy-back guarantee, we settle any remaining deferred balances, in excess of the buy-back payment, to leasing revenue, and we reclassify the net book value of the product on the consolidated balance sheet to "Inventories" or "Property and equipment, net" depending on the intended use at the time. The revenue is being recognized in accordance with Topic 840, Leases . Barrier Rentals - Leasing Fees Leasing fees are paid by customers at the beginning of the lease agreement and are recorded as deferred revenue. The deferred revenue is then recognized each month as lease income for the duration of the lease, in accordance with Topic 840, Leases. Royalty Income The Company licenses certain products to other precast companies to produce the Company's products to engineering specifications under the licensing agreements. The agreements are typically for five year terms and require royalty payments from 4% to 6% of total sales of licensed products, which are paid on a monthly basis. The revenues from licensing agreements are recognized in the month earned, in accordance with Topic 606-10-55-65. Shipping and Installation Shipping and installation revenues are recognized as a distinct performance obligation in the period the shipping and installation services are provided to the customer, in accordance with Topic 606. Disaggregation of Revenue In the following table, revenue is disaggregated by primary sources of revenue (in thousands): Revenue by Type 2018 2017 Change % of Change Product Sales: Soundwall Sales $ 9,867 $ 7,571 $ 2,296 30.3 % Architectural Sales 876 829 47 5.7 % Slenderwall Sales 5,572 2,048 3,524 172.1 % Miscellaneous Sales 1,760 2,793 (1,033 ) (37.0 )% Barrier Sales 7,264 11,276 (4,012 ) (35.6 )% Easi-Set and Easi-Span Building Sales 2,114 2,484 (370 ) (14.9 )% Utility and Farm Product Sales 1,232 1,492 (260 ) (17.4 )% Miscellaneous Product Sales 474 562 (88 ) (15.7 )% Total Product Sales 29,159 29,055 104 0.4 % Barrier Rentals 1,729 4,267 (2,538 ) (59.5 )% Royalty Income 1,675 1,885 (210 ) (11.1 )% Shipping and Installation 7,657 6,510 1,147 17.6 % Total Service Revenue 11,061 12,662 (1,601 ) (12.6 )% Total Revenue $ 40,220 $ 41,717 $ (1,497 ) (3.6 )%