Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Significant estimates used in the preparation of these financial statements include, but are not limited to; the sand reserves and their impact on calculating the depletion expense under the units-of-production method; the depreciation associated with property and equipment, impairment considerations of those assets; estimated cost of future asset retirement obligations; stock-based compensation; recoverability of deferred tax assets; inventory reserve; collectability of receivables; and certain liabilities. Actual results could differ from management’s best estimates as additional information or actual results become available in the future, and those differences could be material.

Revenue Recognition

The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery of products has occurred, the sales price charged is fixed or determinable, collectability is reasonably assured, and the risk of loss is transferred to the customer. The Company’s sales are generally free carrier (“FCA”), payment made at the origination point at the Company’s facility, and title passes as the product is loaded into railcars hired by the customer or provided by the Company. Certain spot-rate customers have shipping terms of FCA, payment made at the destination; the Company recognizes this revenue when the sand is received at the destination.

The Company derives its revenue by mining and processing sand that its customers purchase. Its revenues are primarily a function of the price per ton realized and the volumes sold. In some instances, its revenues also include transportation costs it charges its customers, a monthly charge to reserve sand capacity and shortfall payments due from customers for minimum volume commitments. The Company’s transportation revenue fluctuates based on a number of factors, including the volume of product it transports and the distance between its plant and customers. The Company’s reservation and shortfall revenues are based on negotiated contract terms and are recognized when rights of use are expired.

The Company sells a limited amount of its products under short term price agreements or at prevailing market rates. The majority of the Company’s revenues are realized through take-or-pay supply agreements with six customers. The expiration dates of these contracts range from 2019 through 2020. These agreements define, among other commitments, the volume of product that the Company’s customers must purchase, the volume of product that the Company must provide, and the price that the Company will charge and that its customers will pay for each ton of contracted product. Prices under these agreements are generally indexed to the Average Cushing Oklahoma WTI Spot Prices and contain provisions allowing for adjustments including: (i) annual percentage price increases; or (ii) market factor increases (or in some cases decreases), including a natural gas surcharge/reduction and a propane surcharge/reduction which are applied if the Average Natural Gas Price or the Average Quarterly Mont Belvieu TX Propane Spot Price, respectively, as listed by the U.S. Energy Information Administration, are above or below the applicable benchmark set in the contract for the preceding calendar quarter. As a result, the Company’s realized prices may not grow at rates consistent with broader industry pricing. For example, during periods of rapid price growth, its realized prices may grow more slowly than those of competitors, and during periods of price decline, its realized prices may outperform industry averages. With respect to the take-or-pay arrangements, if the customer is not allowed to make up deficiencies, the Company recognizes revenues of the minimum contracted quantity and minimum contract price, assuming payment has been received or is reasonably assured. If deficiencies can be made up, amounts billed and collected in excess of actual sales are recognized as deferred revenues until production is actually taken by the customer or the right to make up deficiencies expires. These agreements generally provide that, if the Company is unable to deliver the contracted minimum volumes, the customer has the right to purchase replacement product from alternative sources, provided that the inability to supply is not the result of an excusable delay, as defined in these agreements. In the event that the price of the replacement product exceeds the contract price and the inability to supply the contracted minimum volume is not the result of an excusable delay, the Company is responsible for the difference.

The Company also recognizes revenue on the rental of its leased railcar fleet to customers either under long-term contracts or on an as-used basis. For the years ended December 31, 2017, 2016 and 2015, the Company recognized $7,702, $5,732 and $3,543 of railcar revenue, respectively.

For the years ended December 31, 2017, 2016 and 2015, the Company recognized $1,244, $20,902 and $10,095, respectively, of revenue for shortfall payments relating to minimum commitments under take-or-pay contracts.

For the years ended December 31, 2017, 2016 and 2015, the Company recognized $30,000, $15,041 and $1,000, respectively, of monthly reservation charges required under certain customer contracts.

For the years ended December 31, 2017, 2016 and 2015, the Company recognized $48,066, $480 and $2,294, respectively, of revenue generated from transportation.

For the years ended December 31, 2017, 2016 and 2015, the Company determined that no amounts related to minimum commitments under customer contracts were due or payable to the Company.

Amounts invoiced or received from customers in advance of sand deliveries are recorded as deferred revenue.

Accounts and Unbilled Receivables

Accounts receivable represents customer transactions that have been invoiced as of the balance sheet date; unbilled receivables represent customer transactions that have not yet been invoiced as of the balance sheet date. Accounts receivable are due within 30 days, or in accordance with terms agreed upon with customers, and are stated at amounts due from customers net of any allowance for doubtful accounts. The Company considers accounts outstanding longer than the payment terms past due. The Company determines the allowance by considering a number of factors, including the length of time trade accounts receivable are past due, previous loss history, the customer’s current ability to pay its obligation, and the condition of the general economy and the industry as a whole. Accounts receivables are written off when they are deemed uncollectible, and payments subsequently received on such receivables are credited to bad debt expense. As of December 31, 2017 and 2016, the Company determined no allowance for doubtful accounts was necessary. As of December 31, 2017 and 2016, no portion of unbilled revenue represents transactions included in deferred revenue.

Deferred Revenue

The Company receives advance payments from certain customers in order to secure and procure a reliable provision and delivery of product. The Company classifies such advances as current or noncurrent liabilities depending upon the anticipated timing of delivery of the supplied product. Revenue is recognized upon the delivery of the product.

The Company may receive an advance payment from a customer, based on the terms of the customer’s long-term contract, for a certain volume of product to be delivered. Revenue is recognized as product is delivered and the deferred revenue is reduced. The deferred revenue balance at December 31, 2017 and 2016 was $0 and $1,615, respectively, and classified as a current liability in the accompanying consolidated balance sheets.

Transportation

Transportation costs are classified as cost of goods sold. Transportation costs consist of railway transportation and transload costs to deliver products to customers. Cost of sales generated from shipping was $50,313, $1,172 and $2,257 for the years ended December 31, 2017, 2016 and 2015, respectively.

Inventories

The Company’s sand inventory consists of raw material (sand that has been excavated but not processed), work-in-progress (sand that has undergone some but not all processing) and finished goods (sand that has been completely processed and is ready for sale). The spare parts inventory consists of critical spare parts.

Sand inventory is stated at the lower of cost or net realizable value using the average cost method. For the years ended December 31, 2017 and 2016, respectively, the Company had no write-down of inventory as a result of any lower of cost or market assessment. Costs applied to the inventory include direct excavation costs, processing costs, overhead allocation, depreciation and depletion. Stockpile tonnages are calculated by measuring the number of tons added and removed from the stockpile. Costs are calculated on a per ton basis and are applied to the stockpiles based on the number of tons in the stockpile. The Company performs physical inventory measurements at least quarterly to verify the quantity of inventory on hand. Due to variation in sand density and moisture content and production processes utilized to manufacture the Company’s products, physical inventories will not necessarily detect all variances. To mitigate this risk, the Company recognizes a yield adjustment on its inventories.

Spare parts inventory is accounted for on a first-in, first-out basis at the lower of cost or net realizable value.

Deferred Financing Charges

Direct costs incurred in connection with the revolving credit facility have been capitalized and are being amortized using the straight-line method, which approximates the effective interest method, over the life of the debt. Fees attributable to the lender and third parties of $1,372 and $1,178 are presented as components of deferred financing charges since there is no outstanding balance on the revolving credit facility as of December 31, 2017 and 2016, respectively.

Amortization expense of the deferred financing charges of $455, $159 and $251, and accretion expense of debt discount of $0, $263 and $519 are included in interest expense as of December 31, 2017, 2016 and 2015, respectively.

Financial Instruments

The carrying value of the Company’s financial instruments, consisting of cash, accounts receivable, accounts payable and accrued expenses, approximates their fair value due to the short maturity of such instruments. Financial instruments also consist of debt for which fair value approximates carrying values as the debt bears interest at a variable rate which is reflective of current rates otherwise available to the Company. Unless otherwise noted, it is management’s opinion that the Company is not exposed to significant interest, currency or credit risks arising from these financial instruments.

Property, Plant and Equipment

Property, plant and equipment are recorded at cost. Costs related to researching, surveying, drilling, and related activities are recorded at cost and capitalized once a determination has been made that the Company’s property has proven and probable reserves. Capitalized mining costs are depleted using the units-of-production method. Construction in progress is primarily comprised of machinery and equipment which has not been placed in service and is not depreciated until the related assets or improvements are ready to be placed in service. Depreciation is calculated using the straight-line method over the estimated useful lives of the property, plant and equipment, which are:


	Years
Land improvements		10
Plant and buildings		5-15
Real estate properties		10-40
Rail spur		30
Vehicles		3-5
Machinery, equipment and tooling		3-15
Furniture and fixtures		3-10
Deferred mining costs		3

Expenditures for maintenance and repairs are charged against income as incurred; betterments that increase the value or materially extend the life of the related assets are capitalized. Upon sale or disposition of property and equipment, the cost and related accumulated depreciation and amortization are removed from the accounts and any resulting gain or loss is recognized in the consolidated income statements.

Asset Retirement Obligation

The Company estimates the future cost of dismantling, restoring and reclaiming operating excavation sites and related facilities in accordance with federal, state and local regulatory requirements and recognizes reclamation obligations when extraction occurs and records them as liabilities at estimated fair value. In addition, a corresponding increase in the carrying amount of the related asset is recorded and depreciated over such asset’s useful life or the estimated number of years of extraction. The reclamation liability is accreted to expense over the estimated productive life of the related asset and is subject to adjustments to reflect changes in value resulting from the passage of time and revisions to the estimates of either the timing or amount of the reclamation costs. Changes in estimates at inactive mines or mining areas are reflected in earnings in the period an estimate is revised. If the asset retirement obligation is settled for more or less than the carrying amount of the liability, a loss or gain will be recognized, respectively.

Fair Value Measurements

The Company’s financial assets and liabilities are to be measured using inputs from the three levels of the fair value hierarchy, of which the first two are considered observable and the last unobservable, which are as follows:

•

Level 1—Inputs are unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date;

•

Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active or other inputs corroborated by observable market data for substantially the full term of the assets or liabilities; and

•

Level 3—Unobservable inputs that reflect the Company’s assumptions that market participants would use in pricing assets or liabilities based on the best information available.

Stock-Based Compensation

The Company accounts for stock-based compensation in accordance with the provisions of Accounting Standards Codification (“ASC”) - 718, “Compensation—Stock Compensation” (“ASC 718”), which requires the recognition of expense related to the fair value of stock-based compensation awards in the Statements of Operations.

For restricted stock issued to employees and members of the board of directors of the Company (the “Board”) for their services on the Board, the Company estimates the grant date fair value of each share of restricted stock at issuance. For awards subject to service-based vesting conditions, the Company recognizes stock-based compensation expense, net of estimated forfeitures, equal to the grant date fair value of the award on a straight-line basis over the requisite service period, which is generally the vesting term. For awards subject to both performance and service-based vesting conditions, the Company recognizes stock-based compensation expense using the straight-line recognition method when it is probable that the performance condition will be achieved. Forfeitures are required to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

Share-based payments issued to non-employees are recorded at their fair values, and are periodically revalued as the equity instruments vest and are recognized as expense over the related service period in accordance with the provisions of ASC 718 and ASC Topic 505, “Equity”. Prior to the Company’s initial public offering, the grant date fair value was calculated based on a weighted analysis of (i) publicly-traded companies in similar line of business to the Company (market comparable method)—Level 2 inputs, and (ii) discounted cash flows of the Company—Level 3 inputs. Once the Company’s shares became publicly traded on November 4, 2016, the Company began to use the actual market price of its shares as the grant date fair value for restricted stock awards.

Income Taxes

On December 22, 2017, the U.S. Tax Cuts and Jobs Act (the “Tax Reform Act”) was signed into law. Pursuant to the Securities and Exchange Commission Staff Accounting Bulletin No. 118, “Income Tax Accounting Implications of the Tax Cuts and Jobs Act” ("SAB 118"), given the amount and complexity of the changes in tax law resulting from the Tax Reform Act, the Company has not finalized the accounting for the income tax effects of the Tax Reform Act. This includes the re-measurement of deferred taxes. The impact of the Tax Reform Act may differ from this estimate during the one-year measurement period due to, among other things, further refinement of the Company’s calculations, changes in interpretations and assumptions the Company has made, guidance that may be issued and actions the Company may take as a result of the Tax Reform Act. As a result of the Tax Reform Act, the Company recorded a tax benefit of approximately $8.5 million due to a re-measurement of deferred tax assets and liabilities.

The Company applies the provisions of ASC Topic 740, “Income Taxes” (“ASC 740”), which principally utilizes a balance sheet approach to provide for income taxes. Under this method, deferred tax assets and liabilities are recognized for the expected future tax consequences of net operating loss carryforwards and temporary differences between the carrying amounts and the tax bases of assets and liabilities.

ASC 740 clarifies the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements. The impact of an uncertain income tax position on the income tax returns must be recognized at the largest amount that is more-likely-than-not to be required to be recognized upon audit by the relevant taxing authority. This standard also provides guidance on de-recognition, measurement, classification, interest and penalties, accounting for interim periods, disclosure and transition issues with respect to tax positions. The Company includes interest and penalties as a component of income tax expense in the consolidated statement of operations. For the periods presented, no interest and penalties were incurred.

Environmental Matters

The Company is subject to various federal, state and local laws and regulations relating to the protection of the environment. Management has established procedures for the ongoing evaluation of the Company’s operations, to identify potential environmental exposures and to comply with regulatory policies and procedures. Environmental expenditures that relate to current operations are expensed or capitalized as appropriate. Expenditures that relate to an existing condition caused by past operations and do not contribute to current or future revenue generation are expensed as incurred. Liabilities are recorded when environmental costs are probable, and the costs can be reasonably estimated. The Company maintains insurance which may cover, in whole or in part, certain environmental expenditures. As of December 31, 2017 and 2016, there were no material probable environmental matters.

Comprehensive Income

Comprehensive income is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. Comprehensive income was equal to net income for all periods presented.

Segment Information

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions on how to allocate resources and assess performance. The Company’s chief operating decision maker is the chief executive officer. The Company and the chief executive officer view the Company’s operations and manage its business as one operating segment. All long-lived assets of the Company reside in the United States.

Basic and Diluted Net Income Per Share of Common Stock

Basic net income per share of common stock is computed by dividing net income attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, excluding the dilutive effects of Series A Preferred Stock, warrants to purchase common stock and restricted stock. Diluted net income per share of common stock is computed by dividing the net income attributable to common stockholders by the sum of the weighted-average number of shares of common stock outstanding during the period plus the potential dilutive effects of Series A Preferred Stock and warrants to purchase common stock, and restricted stock outstanding during the period calculated in accordance with the treasury stock method, although these shares, restricted stock and warrants are excluded if their effect is anti-dilutive. During the fourth quarter of 2016, the Series A Preferred Stock was fully redeemed and the warrants to purchase common stock were fully exercised. Therefore, for the year ended December 31, 2017, these items have no impact on diluted weighted-average common stock. The following table reconciles the weighted-average common shares outstanding used in the calculation of basic net income per share to the weighted average common shares outstanding used in the calculation of diluted net income per share:

	Year Ended December 31,
	2017		2016		2015
Determination of Shares
Weighted average common shares outstanding		40,208		24,322		22,114
Assumed conversion of warrant		-		-		4,000
Assumed conversion of restricted stock		96		257		286
Diluted weighted average common stock outstanding		40,304		24,579		26,400

Reclassification

Certain 2015 financial statement items have been reclassified to conform to the current financial statement presentation. These reclassifications have no effect on previous reported net income.

Recent Accounting Pronouncements

In August 2017, the FASB issued Accounting Standards Update (“ASU”) 2017-12 “Derivatives and Hedging (Topic 815) Targeted Improvements to Accounting for Hedging Activities”. ASU 2017-12 eliminates the requirement to separately measure and report hedge ineffectiveness and generally requires the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item. The guidance also eases certain documentation and assessment requirements and modifies the accounting for components excluded from the assessment of hedge effectiveness. The guidance is effective for the Company beginning after December 15, 2018, although early adoption is permitted. The Company is currently evaluating the effects of ASU 2017-12 on its consolidated financial statements.

In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230) Classification of Certain Cash Receipts and Cash Payments” (“ASU 2016-15”). ASU 2016-15 eliminates the diversity in practice related to the classification of certain cash receipts and payments for debt prepayment or extinguishment costs, the maturing of a zero-coupon bond, the settlement of contingent liabilities arising from a business combination, proceeds from insurance settlements, distributions from certain equity method investees and beneficial interests obtained in a financial asset securitization. ASU 2016-15 designates the appropriate cash flow classification, including requirements to allocate certain components of these cash receipts and payments among operating, investing and financing activities. The guidance is effective for the Company beginning after December 15, 2017, although early adoption is permitted. Although the Company is still in the process of assessing the impact of the adoption of ASU 2016-15, it does not currently anticipate a material impact on its financial statements.

In February 2016, the FASB issued ASU 2016-02, “Leases (ASC 842)” (“ASU 2016-02”), which replaces the existing guidance in ASC 840, “Leases”. ASC 842 requires lessees to recognize most leases on their balance sheets as lease liabilities with corresponding right of use assets. The new lease standard does not substantially change lessor accounting. The new standard is effective for interim and annual reporting periods beginning after December 15, 2018, with early adoption permitted. The Company is currently in the process of evaluating the impact of the adoption on its consolidated financial statements.

In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09”). The objective of ASU 2014-09 is to establish a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and will supersede most of the existing revenue recognition guidance, including industry specific guidance. The core principle of ASU 2014-09 is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying the new guidance, an entity will: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the contract’s performance obligations; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. ASU 2014-09 applies to all contracts with customers except those that are within the scope of other topics in the FASB ASC. In April and May 2016, the FASB issued ASU 2016-10, “Revenue from Contracts with Customers – Identifying Performance Obligations and Licensing”, ASU 2016-11, “Revenue Recognition and Derivatives and Hedging – Recession of SEC Guidance”, ASU 2016-12, “Revenue from Contracts with Customers – Narrow-Scope Improvements and Practical Expedients”, and ASU 2016-20, “Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers”. These ASUs each affect the guidance of the new revenue recognition standard in ASU 2014-09 and related subsequent ASUs. The new guidance is effective for annual reporting periods (including interim periods within those periods) beginning after December 15, 2017 for public companies. Early adoption is only permitted as of annual reporting periods beginning after December 15, 2016. Entities have the option of using either a full retrospective or modified approach to adopt ASU 2014-09.

On January 1, 2018, we adopted the new accounting standard ASC 606, “Revenue from Contracts with Customers and all the related amendments” (“ASC 606”) to all contracts which were not completed or expired as of January 1, 2018 using the modified retrospective method. We will recognize the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of retained earnings. Results for reporting periods beginning after January 1, 2018 will be presented under ASC 606, while the comparative information will not be restated and will continue to be reported under the accounting standards in effect for those periods. We expect the impact of the adoption of the new standard to be immaterial to our revenue and net income on an ongoing basis.

With the adoption of the standard, the consolidated financial statements will be supplemented by new disclosure requirements. Areas of focus and updated presentation requirements include disclosures surrounding contracts with customers, disaggregation of revenue, contract balances, performance obligations, significant judgements used in the application of the guidance and transaction price allocation to remaining performance obligations.

Revenue Recognition

Revenues are recognized when control of the promised goods or services is transferred to our customers, the amount of which reflects the consideration the Company expects to be entitled to in exchange for those goods or services.

Sand Sales Revenue

The Company derives its revenue by mining and processing sand. Its revenues are primarily a function of the price per ton realized and the volumes sold. The Company’s sales are generally FCA, payment made at the origination point at the Company’s facility, title passes as the product is loaded into railcars hired by the customer or provided by the Company, and revenue is recognized when title transfers at the Company’s facility. Certain spot-rate customers have shipping terms of FCA; the Company recognizes this revenue when the sand is received at the destination.

Prices under these agreements are generally indexed to the Average Cushing Oklahoma WTI Spot Prices and contain provisions allowing for adjustments including: (i) annual percentage price increases; or (ii) market factor increases, including a natural gas surcharge/reduction and a propane surcharge/reduction which are applied if the Average Natural Gas Price or the Average Quarterly Mont Belvieu TX Propane Spot Price, respectively, as listed by the U.S. Energy Information Administration, are above or below the applicable benchmark set in the contract for the preceding calendar quarter.

Reservation Charges

The Company requires certain customers to pay a fixed-price monthly reservation charge based on a minimum contractual volume over the remaining life of their contract, which may be applied as a per ton credit to the sales price up to a certain contractually specified monthly volume or credited against any applicable shortfall payments.

Shortfall Payments

The Company’s shortfall revenues are based on negotiated contract terms and are recognized when rights of use are expired. The Company recognizes revenue to the extent of the unfulfilled minimum contracted quantity at the shortfall price per ton as stated in the contract once payment is received or probable.

Railcar Rental

Railcar rentals consists of revenue derived from the leasing of the Company’s railcars to customers under long-term contracts or on an as-used basis. Based on the customer contract, the Company either recognizes revenue on the leasing of railcars based on when the terms of the agreement state that the railcar is available to the customer for use, or based on a specified price per ton shipped. The Company recognizes revenue from leasing in accordance with ASC 840, as leasing revenue does not meet the criteria of ASC 606.

Transportation Revenue

Transportation revenue consists of primarily pass-through railway transportation and revenue to deliver products to customers. The Company’s transportation revenue fluctuates based on many factors, including the volume of product it transports and the distance between its plant and customers.

Contract Balances

The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables, and deferred revenue on the consolidated balance sheet. For the Company’s sand sales, amounts are billed as sand is loaded on the railcars to fill customer orders for free carrier origination point sales or when sand is received at the destination for free carrier destination point sales and recorded as accounts receivable. For the Company’s freight revenue, amounts billed depend on the shipping terms and are recorded as receivables accordingly. Generally, billing occurs subsequent to revenue recognition, resulting in contract assets. In addition, the Company sometimes receives shortfall and reservation payments from its customers and recognizes the revenue once the rights of use are expired. Changes in the contract asset and liability balances during the year ended December 31, 2017 were not materially impacted by any other factors.

Deferred Revenues

Revenue recognized for the year ended December 31, 2017 that was included in the contract liability balance at the beginning of the year was $1,615.

Performance Obligations

A performance obligation is a promise in a contract to transfer a distinct good or service to the customer, and is the unit of account in accordance with ASC 606. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. Generally, the Company’s contracts include a single performance obligation that is separately identifiable, and therefore, distinct. Under ASC 606, the allocation of transaction price is not necessary if only one performance obligation is identified. The Company expects to recognize approximately 42% of this remaining performance obligation as revenue throughout the remainder of 2018, and the remaining 58% by 2021.

Revenue from sand sales are recognized at a point in time, either upon shipment or upon delivery, and accounted for 37% of the Company’s revenue for the year ended December 31, 2017. Revenue from reservation charges and shortfall revenues are recognized at a point in time, when the right of use expires, and accounted for 22% and 1% of revenue for the year ended December 31, 2017, respectively. Revenue from railcar rental and transportation is recognized at a point in time, upon shipment, and accounted for 5% and 35% of revenue for the year ended December 31, 2017, respectively.

Significant Judgments

Accounting for long-term contracts involves the use of various techniques to estimate total contract revenue, costs and satisfaction of performance obligation. The Company satisfies its performance obligation and subsequently recognizes revenue, at a point in time, upon shipment of the products as the customer obtains control over the goods once the sand is loaded into the railcars or sand is delivered to the customer’s destination. In the case of frac sand being delivered to customers, the transaction price is variable in nature and is directly tied to the Average Cushing Oklahoma WTI Spot Prices per barrel. There were no changes to the significant judgments used by the Company to determine the timing of satisfaction of the performance obligation under ASC 606.

Costs to Obtain or Fulfill Contract

The Company’s incremental cost to fulfill or obtain contracts with customers primarily consist of commissions and legal costs. Under take-or-pay contracts, the Company provides sales team members with commissions at set per ton prices. These commissions are paid on a monthly basis, when and if the sand is taken by the customer. Because sales associates receive commissions when orders are fulfilled, the Company did not record any assets for commissions at December 31, 2017. The Company also incurs legal costs relating to the drafting and negotiating of a contract with select customers. Because these costs do not directly relate to the future ability to perform the contract, there were no legal costs capitalized as of December 31, 2017. The Company did not record amortization of costs incurred to obtain the contract or any impairment losses for the period ending December 31, 2017.