Natural Gas Services (NGS) 10-Q 8 Nov 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Oct. 28, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	1-31398
Entity Registrant Name	NATURAL GAS SERVICES GROUP, INC.
Entity Incorporation, State or Country Code	CO
Entity Tax Identification Number	75-2811855
Entity Address, Address Line One	404 Veterans Airpark Ln., Ste 300
Entity Address, City or Town	Midland
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	79705
City Area Code	432
Local Phone Number	262-2700
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		13,470,397
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	NGS
Security Exchange Name	NYSE
Amendment Flag	false
Entity Central Index Key	0001084991
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2019
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current Assets:
Cash and cash equivalents	$ 19,482	$ 52,628
Trade accounts receivable, net of allowance for doubtful accounts of $325 and $291, respectively	11,224	7,219
Inventory	30,289	30,974
Prepaid income taxes	3,102	3,148
Prepaid expenses and other	1,320	2,430
Total current assets	65,417	96,399
Long-term inventory, net of allowance of $3,371 and $19, respectively	540	3,980
Rental equipment, net of accumulated depreciation of $156,800 and $165,428, respectively	205,741	175,886
Property and equipment, net of accumulated depreciation of $12,317 and $11,556, respectively	22,101	16,587
Right of use assets - operating leases, net of accumulated amortization $130	447	0
Goodwill	0	10,039
Intangibles, net of accumulated amortization of $1,852 and $1,758, respectively	1,307	1,401
Other assets	1,443	1,109
Total assets	296,996	305,401
Current Liabilities:
Accounts payable	4,183	2,122
Accrued liabilities	8,358	8,743
Current operating leases	107	0
Deferred income	81	81
Total current liabilities	12,729	10,946
Line of credit	417	417
Deferred income tax liability	31,229	32,158
Long-term operating leases	340	0
Other long-term liabilities	1,790	1,699
Total liabilities	46,505	45,220
Commitments and contingencies (Notes 8 and 11)
Stockholders’ Equity:
Preferred stock, 5,000 shares authorized, no shares issued or outstanding	0	0
Common stock, 30,000 shares authorized, par value $0.01; 13,142 and 13,005 shares issued, respectively	131	130
Additional paid-in capital	109,861	107,760
Retained earnings	140,989	152,291
Treasury Shares, at cost, 38 shares	(490)	0
Total stockholders' equity	250,491	260,181
Total liabilities and stockholders' equity	$ 296,996	$ 305,401

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current Assets:
Allowance for doubtful accounts	$ 325	$ 291
Allowance for obsolescence	3,371	19
Noncurrent Assets:
Accumulated depreciation, rental equipment	156,800	165,428
Accumulated depreciation, property and equipment	12,317	11,556
Accumulated amortization, operating lease right of use assets	130
Accumulated amortization, intangibles	$ 1,852	$ 1,758
Stockholders’ Equity:
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Common stock, shares issued (in shares)	13,142,000	13,005,000
Common stock, shares outstanding (in shares)	13,142,000	13,005,000
Treasury shares (in shares)	38,000

Condensed Consolidated Income S

Condensed Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue:
Revenue	$ 20,852	$ 16,396	$ 58,738	$ 49,318
Operating costs and expenses:
Cost of rentals, exclusive of depreciation stated separately below	6,300	5,363	18,544	15,262
Cost of sales, exclusive of depreciation stated separately below	4,390	3,081	12,508	10,196
Cost of service and maintenance	164	107	470	273
Selling, general and administrative expense	2,791	2,353	7,966	6,683
Depreciation and amortization	5,867	5,536	17,108	16,372
Impairment of goodwill	10,039	0	10,039	0
Inventory allowance and retirement of rental equipment	4,862	0	4,862	0
Total operating costs and expenses	34,413	16,440	71,497	48,786
Operating (loss) income	(13,561)	(44)	(12,759)	532
Other income (expense):
Interest expense	(4)	(4)	(12)	(10)
Other income, net	93	184	579	189
Total other income, net	89	180	567	179
(Loss) Income before provision for income taxes	(13,472)	136	(12,192)	711
Income tax benefit (expense)	1,240	100	890	(3)
Net (loss) income	$ (12,232)	$ 236	$ (11,302)	$ 708
(Loss) Earnings per share:
Basic (in USD per share)	$ (0.93)	$ 0.02	$ (0.86)	$ 0.05
Diluted (in USD per share)	$ (0.93)	$ 0.02	$ (0.86)	$ 0.05
Weighted average shares outstanding:
Basic (in shares)	13,137	12,977	13,112	12,953
Diluted (in shares)	13,137	13,254	13,112	13,228
Rental
Revenue:
Revenue	$ 14,434	$ 12,039	$ 41,393	$ 34,937
Other income (expense):
Total other income, net	0	0	0	0
(Loss) Income before provision for income taxes	5,635	6,676	20,350	19,675
Sales
Revenue:
Revenue	5,877	3,947	15,816	13,328
Service and maintenance
Revenue:
Revenue	541	410	1,529	1,053
Other income (expense):
Total other income, net	0	0	0	0
(Loss) Income before provision for income taxes	$ 377	$ 303	$ 1,059	$ 780

Condensed Consolidated Statemen

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock
Balance, beginning of period (in shares) at Dec. 31, 2017		0	12,880,000			0
Balance, beginning of period at Dec. 31, 2017	$ 257,319	$ 0	$ 129	$ 105,325	$ 151,865	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options, shares (in shares)			9,000
Exercise of common stock options	157			157
Compensation expense on common stock options	66			66
Issuance of restricted stock, shares (in shares)			60,000
Issuance of restricted stock	0
Compensation expense on restricted common stock	362			362
Taxes paid related to net shares settlement of equity awards	(495)			(495)
Net (loss) income	225				225
Balance, end of period (in shares) at Mar. 31, 2018		0	12,949,000			0
Balance, end of period at Mar. 31, 2018	257,634	$ 0	$ 129	105,415	152,090	$ 0
Balance, beginning of period (in shares) at Dec. 31, 2017		0	12,880,000			0
Balance, beginning of period at Dec. 31, 2017	257,319	$ 0	$ 129	105,325	151,865	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	708
Balance, end of period (in shares) at Sep. 30, 2018		0	13,001,000			0
Balance, end of period at Sep. 30, 2018	259,807	$ 0	$ 130	107,104	152,573	$ 0
Balance, beginning of period (in shares) at Mar. 31, 2018		0	12,949,000			0
Balance, beginning of period at Mar. 31, 2018	257,634	$ 0	$ 129	105,415	152,090	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation expense on common stock options	31			31
Issuance of restricted stock, shares (in shares)			19,000
Issuance of restricted stock	0
Compensation expense on restricted common stock	617		$ 1	616
Taxes paid related to net shares settlement of equity awards	(134)			(134)
Net (loss) income	247				247
Balance, end of period (in shares) at Jun. 30, 2018		0	12,968,000			0
Balance, end of period at Jun. 30, 2018	258,395	$ 0	$ 130	105,928	152,337	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options, shares (in shares)			29,000
Exercise of common stock options	522			522
Compensation expense on common stock options	30			30
Issuance of restricted stock, shares (in shares)			4,000
Issuance of restricted stock	0
Compensation expense on restricted common stock	624			624
Net (loss) income	236				236
Balance, end of period (in shares) at Sep. 30, 2018		0	13,001,000			0
Balance, end of period at Sep. 30, 2018	259,807	$ 0	$ 130	107,104	152,573	$ 0
Balance, beginning of period (in shares) at Dec. 31, 2018		0	13,005,000			0
Balance, beginning of period at Dec. 31, 2018	260,181	$ 0	$ 130	107,760	152,291	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options, shares (in shares)			57,000
Exercise of common stock options	555			555
Compensation expense on common stock options	31			31
Issuance of restricted stock, shares (in shares)			71,000
Issuance of restricted stock	0
Compensation expense on restricted common stock	464		$ 1	463
Taxes paid related to net shares settlement of equity awards	(192)			(192)
Net (loss) income	357				357
Balance, end of period (in shares) at Mar. 31, 2019		0	13,133,000			0
Balance, end of period at Mar. 31, 2019	261,396	$ 0	$ 131	108,617	152,648	$ 0
Balance, beginning of period (in shares) at Dec. 31, 2018		0	13,005,000			0
Balance, beginning of period at Dec. 31, 2018	$ 260,181	$ 0	$ 130	107,760	152,291	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase of treasury shares (in shares)	37,936
Purchase of treasury shares	$ (490)
Net (loss) income	(11,302)
Balance, end of period (in shares) at Sep. 30, 2019		0	13,142,000			(38,000)
Balance, end of period at Sep. 30, 2019	250,491	$ 0	$ 131	109,861	140,989	$ (490)
Balance, beginning of period (in shares) at Mar. 31, 2019		0	13,133,000			0
Balance, beginning of period at Mar. 31, 2019	261,396	$ 0	$ 131	108,617	152,648	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options, shares (in shares)			0
Exercise of common stock options	(50)			(50)
Compensation expense on common stock options	30			30
Issuance of restricted stock, shares (in shares)			5,000
Issuance of restricted stock	0
Compensation expense on restricted common stock	612		$ 0	612
Taxes paid related to net shares settlement of equity awards	9			9
Net (loss) income	573				573
Balance, end of period (in shares) at Jun. 30, 2019		0	13,138,000			0
Balance, end of period at Jun. 30, 2019	262,570	$ 0	$ 131	109,218	153,221	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation expense on common stock options	32			32
Issuance of restricted stock, shares (in shares)			4,000
Issuance of restricted stock	0
Compensation expense on restricted common stock	611			611
Purchase of treasury shares (in shares)						(38,000)
Purchase of treasury shares	(490)					$ (490)
Net (loss) income	(12,232)				(12,232)
Balance, end of period (in shares) at Sep. 30, 2019		0	13,142,000			(38,000)
Balance, end of period at Sep. 30, 2019	$ 250,491	$ 0	$ 131	$ 109,861	$ 140,989	$ (490)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income	$ (11,302)	$ 708
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	17,108	16,372
Deferred income taxes	(929)	133
Stock-based compensation	1,780	1,729
Bad debt allowance (recovery)	55	(137)
Inventory allowance	3,350	0
Impairment of goodwill	10,039	0
Gain on sale of assets	(37)	(49)
Retirement of rental equipment	1,512	0
(Gain) loss on company owned life insurance	(145)	15
Changes in operating assets and liabilities:
Trade accounts receivables	(4,060)	555
Inventory	1,861	6,307
Prepaid expenses and prepaid income taxes	198	(416)
Accounts payable and accrued liabilities	1,054	(2,397)
Deferred income	0	(51)
Other	125	267
NET CASH PROVIDED BY OPERATING ACTIVITIES	20,609	23,036
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of rental equipment and property and equipment	(53,401)	(28,815)
Purchase of company owned life insurance	(207)	(237)
Proceeds from sale of property and equipment	26	49
Proceeds from insurance claims of property and equipment	11	0
NET CASH USED IN INVESTING ACTIVITIES	(53,571)	(29,003)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments from other long-term liabilities, net	(16)	(25)
Proceeds from exercise of stock options	505	680
Purchase of treasury shares	(490)	0
Taxes paid related to net share settlement of equity awards	(183)	(629)
NET CASH (USED IN) PROVIDED BY FINANCING ACTIVITIES	(184)	26
NET CHANGE IN CASH AND CASH EQUIVALENTS	(33,146)	(5,941)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	52,628	69,208
CASH AND CASH EQUIVALENTS AT END OF PERIOD	19,482	63,267
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Interest paid	43	10
Income taxes paid	254	66
NON-CASH TRANSACTIONS
Transfer of rental equipment components to inventory	746	144
Transfer of prepaids to rental equipment and inventory	958	$ 0
Right of use acquired through an operating lease	$ 126

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Basis of Presentation and Summary of Significant Accounting Policies These notes apply to the unaudited condensed consolidated financial statements of Natural Gas Services Group, Inc. a Colorado corporation (the "Company", “NGSG”, "Natural Gas Services Group", "we" or "our"). The accompanying unaudited condensed consolidated financial statements include the accounts of the Company, its subsidiary, NGSG Properties, LLC and the rabbi trust associated with the Company's deferred compensation plan (see Note 5). All significant intercompany accounts and transactions for the periods presented have been eliminated in consolidation. These financial statements include all adjustments, consisting of only normal recurring adjustments, which are necessary to make our financial position at September 30, 2019 and the results of our operations for the three and nine months ended September 30, 2019 and 2018 not misleading. As permitted by the rules and regulations of the Securities and Exchange Commission (SEC), the accompanying condensed consolidated financial statements do not include all disclosures normally required by generally accepted accounting principles in the United States of America (GAAP). These financial statements should be read in conjunction with the financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2018 on file with the SEC. In our opinion, the condensed consolidated financial statements are a fair presentation of the financial position, results of operations, changes in stockholders' equity and cash flows for the periods presented. The results of operations for the three and nine months ended September 30, 2019 are not necessarily indicative of the results of operations to be expected for the full fiscal year ending December 31, 2019. Revenue Recognition Policy The Company adopted ASC 606, Revenue from Contracts with Customers ("ASC 606") on January 1, 2018. As a result, the Company has changed its accounting policy for revenue recognition as detailed below. The Company applied ASC 606 using the cumulative effect method. We had no significant changes in our recognition of revenue at adoption and our review of all open revenue from contracts with customers on January 1, 2018 indicated we had no adjustment to be made. If an adjustment had been needed, we would have recognized the cumulative effect of initially applying ASC 606 with an adjustment to the opening balance of equity at January 1, 2018. Revenue is measured based on a consideration specified in a customer’s contract, excluding any sale incentives and taxes collected on behalf of third parties (i.e. sales and property taxes). We recognize revenue once our performance obligation has been satisfied and control over a product or service has transferred to the customer. Shipping and handling costs incurred are accounted for as fulfillment costs and are included in cost of revenues in our condensed consolidated income statement. Nature of Goods and Services The following is a description of principal activities from which the Company generates its revenue: Rental Revenue. The Company generates revenue from renting compressors and flare systems to our customers. These contracts may also include a fee for servicing the compressor or flare during the rental contract. Our rental contracts generally range from six to 60 months, with our larger horsepower compressors having longer minimum contract terms. Our rental revenue is recognized over time, with equal monthly payments over the term of the contract. After the term of a contract has expired, a customer may renew their contract or continue renting on a monthly basis thereafter. In accordance ASC 842 – Leases, we have applied the practical expedient ASC 842-10-15-42A, which allows the Company to combine lease and non-lease components. Sales Revenue. The Company generates revenue by the sale of custom/fabricated compressors, flare systems, and parts, as well as, exchange/rebuilding customer owned compressors and sale of used rental equipment. Custom/fabricated compressors and flare systems - The Company designs and fabricates compressors and flares based on the customer’s specifications outlined in their contract. Though the equipment being built is customized by the customer, control under these contracts does not pass to the customer until the compressor or flare package is complete and shipped, or in accordance with a bill and hold arrangements the customer accepts title and assumes the risk and rewards of ownership. We request some of our customers to make progressive payments as the product is being built; these payments are recorded as a contract liability on the Deferred Income line on the condensed consolidated balance sheet until control has been transferred. These contracts also may include an assurance warranty clause to guarantee the product is free from defects in material and workmanship for a set duration of time; this is a standard industry practice and is not considered a performance obligation. From time to time, upon the customer’s written request, we recognize revenue when manufacturing is complete and the equipment is ready for shipment. At the customer’s request, we will bill the customer upon completing all performance obligations, but before shipment. The customer will formally request that we ship the equipment per their direction from our manufacturing facility at a later specified date and that we segregate the equipment from our finished goods, such that they are not available to fill other orders. Per the customer’s agreement change of control is passed to the customer once the equipment is complete and ready for shipment. We have operated using bill and hold agreements with certain customers for many years, with consistent satisfactory results for both the customer and us. The credit terms on these agreements are consistent with the credit terms on all other sales. All control is shouldered by the customer and there are no exceptions to the customer’s commitment to accept and pay for the manufactured equipment. Revenues recognized related to bill and hold arrangements for the nine months ended September 30, 2019 was approximately $9.4 million. Parts - Revenue is recognized after the customer obtains control of the parts. Control is passed either by the customer taking physical possession or the parts being shipped. The amount of revenue recognized is not adjusted for expected returns, as our historical part returns have been de minimis. Exchange or rebuilding customer owned compressors - Based on the contract, the Company will either exchange a new/rebuilt compressor for the customer’s malfunctioning compressor or rebuild the customer’s compressor. Revenue is recognized after control of the replacement compressor has transferred to the customer by physical delivery, delivery and installment or shipment of the compressor. Used compressors or flares - From time to time, a customer may request to purchase a used compressor or flare out of our rental fleet. Revenue from the sale of rental equipment is recognized when the control has passed to the customer, when the customer has taken physical possession or the equipment has been shipped. Service and Maintenance Revenue . The Company provides routine or call-out services on customer owned equipment. Revenue is recognized after services in the contract are rendered. Payment terms for sales revenue and service and maintenance revenue discussed above are generally 30 to 60 days although terms for specific customers can vary. Also, transaction prices are not subject to variable consideration constraints. Disaggregation of Revenue The following table shows the Company's revenue disaggregated by product or service type for the three and nine months ended September 30, 2019 and 2018: Three months ended September 30, Nine months ended September 30, (in thousands) (in thousands) 2019 2018 2019 2018 Compressors - sales $ 4,703 $ 2,891 $ 12,199 $ 9,454 Flares - sales 243 336 783 1,827 Other (Parts/Rebuilds) - sales 931 720 2,834 2,047 Service and maintenance 541 410 1,529 1,053 Total revenue from contracts with customers 6,418 4,357 17,345 14,381 Add: non-ASC 606 rental revenue 14,434 12,039 41,393 34,937 Total revenue $ 20,852 $ 16,396 $ 58,738 $ 49,318 Contract Balances As of September 30, 2019 and December 31, 2018, we had the following receivables and deferred income from contracts with customers: September 30, 2019 December 31, 2018 (in thousands) Accounts Receivable Accounts receivable - contracts with customers $ 4,038 $ 2,250 Accounts receivable - non-ASC 606 7,511 5,260 Total Accounts Receivable $ 11,549 $ 7,510 Less: Allowance for doubtful accounts (325) (291) Total Accounts Receivable, net $ 11,224 $ 7,219 Deferred income $ 81 $ 81 The Company recognized $47,000 in revenue for the nine months ended September 30, 2019 that was included in deferred income at the beginning of 2019. For the year ended December 31, 2018, the Company recognized revenue of $176,000 from amounts related to sales that were included in deferred income at the beginning of 2018. The changes in the balance of accounts receivable and deferred income were primarily due to normal timing differences between our performance and the customers’ payments. Transaction Price Allocated to the Remaining Performance Obligations As of September 30, 2019, the Company did not have revenue related to performance obligations under ASC 606-10-50-13. Contract Costs The Company applies the practical expedient in ASC 340-40-25-4 and recognizes the incremental costs of obtaining contracts as an expense when incurred if the amortization period of the assets that the Company otherwise would have recognized is one year or less. These costs are included in selling, general and administrative expense on our consolidated income statement. Leases On January 1, 2019, we adopted ASC 842, Leases ("ASC 842") and all the related amendments using the modified retrospective method. We recognized the cumulative effect of initially applying the new lease standard and had no adjustments to retained earnings. The comparative information has not been restated and continues to be reported under the lease accounting standard in effect for those periods. We do not expect the adoption of the new lease standard to have a material impact to our net income on an ongoing basis. The new lease standard requires all leases to be reported on the balance sheet as right-of-use assets and lease obligations. We elected the practical expedients permitted under the transition guidance of the new standard that retained the lease classification and initial direct costs for any leases that existed prior to adoption of the standard. We did not reassess whether any contracts or land easements entered into prior to adoption are leases or contain leases. The cumulative effect of the changes made to our consolidated balance sheet at January 1, 2019, for the adoption of ASU 2016-02, Leases, was as follows (in thousands): Balance at December 31, 2018 Adjustments due to ASU 2016-02 Balance at January 1, 2019 Balance Sheet Assets Right of use assets $ — $ 451 $ 451 Liabilities Current portion of operating leases $ — $ 126 $ 126 Long term portion of operating leases — 325 325 Total lease liabilities $ — $ 451 $ 451 The Company, as a lessee, applies the practical expedient in ASC 842-10-15-37, and does not separate non-lease components from lease components, therefore, accounting for each separate lease component and its associated non-lease component, as a single lease component. The Company, as a lessor, applies the practical expedient in ASC 842-10-15-42A, in leases that contain the same timing and pattern of transfer for lease and non-lease components and are deemed operating leases, the lessor is not required to separate non-lease components from lease components. Therefore, on any lease that meets these qualifications we have chosen to account for each separate lease component and its associated non-lease component, as a single lease component. The Company applies the practical expedient in ASC 842-20-25-2, to recognize the lease payments in profit or loss on a straight-line basis over the lease term and variable lease payments in the period in which the obligation for those payments is incurred for leases with terms of 12 months or less. Fair Value of Financial Instruments Our financial instruments consist principally of cash and cash equivalents, accounts receivable, accounts payable, deferred compensation plan (cash portion) and our line of credit. Pursuant to ASC 820 (Accounting Standards Codification), the fair value of our cash equivalents is determined based on “Level 1” inputs, which consist of quoted prices in active markets for identical assets. We believe that the recorded values of all of our other financial instruments approximate their fair values because of their nature (variable rate debt) and relatively short maturity dates or durations. Income Taxes As part of the process of preparing our financial statements, we are required to estimate our federal income taxes as well as income taxes in each of the states in which we operate. We use an estimated annual effective tax rate for purposes of determining the income tax provision during interim reporting periods. In calculating our estimated annual effective tax rate, we consider forecasted annual pre-tax income and estimated permanent book versus tax differences, as well as tax credits. Adjustments to the effective tax rate and estimate will occur as information and assumptions change.This process involves us estimating our actual current tax exposure together with assessing temporary differences resulting from differing treatment of items for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included in our consolidated balance sheet. We must then assess the likelihood that our deferred tax assets will be recovered from future taxable income and, to the extent we believe that recovery is not probable, we must establish a valuation allowance. To the extent we establish a valuation allowance or increase this allowance in a period, we must include an expense in the tax provision in the statement of operations. Significant management judgment is required in determining our provision for income taxes, our deferred tax assets and liabilities and any valuation allowance recorded against our net deferred tax assets. We currently have no valuation allowance and fully expect to utilize all of our deferred tax assets. ASC Topic 740 prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. In order to record any financial statement benefit, we are required to determine, based on technical merits of the position, whether it is more likely than not (a likelihood of more than 50 percent) that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes. If that step is satisfied, then we must measure the tax position to determine the amount of benefit to recognize in the financial statements. The tax position is measured at the largest amount of the benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement. Our policy regarding income tax interest and penalties is to expense those items as other expense. During the fourth quarter of 2018, the Company discovered a potential uncertain tax position attributable to the deductibility of certain executive compensation expense for federal income tax purposes aggregating approximately $168,000, $149,000 and $230,000 for the years ended December 31, 2017, 2016 and 2015, respectively. As a result, in accordance with ASC Topic 740, during the fourth quarter of 2018, the Company recorded a tax adjustment of $547,000 and accrued penalty and interest expense of $55,000 attributable to the uncertain tax position. The Company's management determined the effect of the potential uncertain tax position on previously reported results of operations for the years ended December 31, 2017 and 2016 was not material. As of September 30, 2019, the Company has filed an amended tax return for the year ended 2015 and has recognized certain offsetting deductions thus reducing our uncertain tax position reserve for 2015, 2016 and 2017. Accrued interest and penalties at September 30, 2019 related to 2016 and 2017 uncertain tax position was approximately $23,000. The Company plans on amending it's 2016 and 2017 filed federal income tax returns and is still in the process of analyzing certain offsetting deductions to reduce the uncertain tax position reserve. We account for uncertain tax positions in accordance with guidance in FASB ASC 740, which prescribes the minimum recognition threshold a tax position taken or expected to be taken in a tax return is required to meet before being recognized in the financial statements. A reconciliation of uncertain tax positions of the beginning and ending amount of uncertain tax positions is as follows (in thousands): Balance at January 1, 2019 $ 578 Additions based on tax positions related to current year — Reductions for tax positions of prior years (319) Balance at September 30, 2019 $ 259 Reclassification of Prior Period Balances Certain reclassifications have been made to prior period amounts, due to our adoption of ASC 842, to conform to the current-year presentation. These reclassifications had no effect on the financial statements.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Stock Options: A summary of option activity under our 1998 Stock Option Plan as of December 31, 2018, and changes during the nine months ended September 30, 2019 is presented below. Number of Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (years) Aggregate Intrinsic Value (in thousands) Outstanding, December 31, 2018 283,686 $ 20.46 3.58 $ 434 Exercised (56,352) 8.97 — 474 Canceled/Forfeited (3,000) 27.91 — — Outstanding, September 30, 2019 224,334 $ 23.25 3.67 $ — Exercisable, September 30, 2019 213,901 $ 23.01 3.49 $ — The following table summarizes information about our stock options outstanding at September 30, 2019: Range of Exercise Prices Options Outstanding Options Exercisable Shares Weighted Average Remaining Contractual Life (years) Weighted Average Exercise Price Shares Weighted Average Exercise Price $0.01-15.70 8,500 2.32 $ 14.89 8,500 $ 14.89 $15.71-17.81 42,000 0.82 17.54 42,000 17.54 $17.82-20.48 50,500 1.59 19.43 50,500 19.43 $20.49-33.36 123,334 5.59 27.33 112,901 27.26 224,334 3.67 $ 23.25 213,901 $ 23.01 The summary of the status of our unvested stock options as of December 31, 2018 and changes during the nine months ended September 30, 2019 is presented below. Unvested stock options: Shares Weighted Average Grant Date Fair Value Per Share Unvested at December 31, 2018 20,865 $ 11.93 Vested (10,432) 11.93 Unvested at September 30, 2019 10,433 $ 11.93 As of September 30, 2019, there was $46,105 of unrecognized compensation cost related to unvested options. Such cost is expected to be recognized over a weighted-average period of one year. Total compensation expense for stock options was $91,984 and $127,055 for the nine months ended September 30, 2019 and 2018, respectively. Restricted Shares/Units:

Inventory

Inventory	9 Months Ended
	Sep. 30, 2019
Inventory Disclosure [Abstract]
Inventory	Inventory Our inventory, net of allowance for obsolescence of $3.4 million at September 30, 2019 and $19,000 December 31, 2018 consisted of the following amounts: September 30, 2019 December 31, 2018 (in thousands) Raw materials - current $ 23,893 $ 26,152 Raw materials - long term, net 540 3,980 Finished Goods 1,022 1,022 Work in process 5,374 3,800 $ 30,829 $ 34,954

Inventory Allowance and Retirem

Inventory Allowance and Retirement of Long-Lived Assets	9 Months Ended
	Sep. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Inventory Allowance and Retirement of Long-Lived Assets	Inventory Allowance and Retirement of Long-Lived Assets Given its concerns about the current industry and broader economic backdrop, Company management conducted a detailed review of our rental compressor units and initiated a thorough inventory analysis during the third quarter of 2019. Due to the slow moving nature or obsolescence of long-term inventory and inventory related to the retirement of rental equipment, management recorded an increase of $3.4 million in the inventory allowance reserve for costs that may not be recoverable in the future.During the review of our rental compressor units, management looked for any units that were not of the type, configuration, make or model that our customers are demanding or that were not cost efficient to refurbish, maintain and/or operate. As a result of this review, we determined 327 units should be retired from our rental fleet. We performed an optimization review and recorded a $1.5 million loss on retirement of rental equipment to reduce the book value of each unit to zero.

Deferred Compensation Plan

Deferred Compensation Plan	9 Months Ended
	Sep. 30, 2019
Postemployment Benefits [Abstract]
Deferred Compensation Plan	Deferred Compensation Plan The Company has a non-qualified deferred compensation plan for executive officers, directors and certain eligible employees. The assets of the deferred compensation plan are held in a rabbi trust and are subject to additional risk of loss in the event of bankruptcy or insolvency of the Company. The plan allows for deferral of up to 90% of a participant’s base salary, bonus, commissions, director fees and restricted stock unit awards. A Company owned life insurance policy held in a rabbi trust is utilized as a source of funding for the plan. The cash surrender value of the life insurance policy is $1.4 million and $1.1 million as of September 30, 2019 and 2018, respectively. For the nine months ending September 30, 2019, we reported in other income (expense) in the consolidated income statement a gain related to the policy of approximately $145,000 and for the same period in 2018, a loss of approximately $15,000. For deferrals of base salary, bonus, commissions and director fees, settlement payments are made to participants in cash, either in a lump sum or in periodic installments. The obligation to pay the deferred compensation and the deferred director fees is adjusted to reflect the positive or negative performance of investment measurement options selected by each participant and was $1.5 million and $1.2 million as of September 30, 2019 and 2018, respectively. The deferred obligation is included in other long-term liabilities in the condensed consolidated balance sheet. For deferrals of restricted stock units, the plan does not allow for diversification, therefore, distributions are paid in shares of common stock and the obligation is carried at grant value. As of September 30, 2019 and 2018, respectively, we have 94,148 and 102,793 unvested restricted stock units being deferred. As of September 30, 2019 and 2018, respectively we have released and issued 80,604 and 33,834 shares to the deferred compensation plan with a value of $1.7 million and $857,000, respectively.

Goodwill

Goodwill	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill Goodwill is tested annually for impairment or as needed upon the occurrence of certain events or substantive changes in circumstances that indicate goodwill is more likely than not impaired. In the last several months, the Company experienced a significant decline in stock price, which is reflective of the significant deterioration of stock prices of companies throughout the oilfield services sector. Accordingly, we calculated our market capitalization (based on our closing stock price) as of September 30, 2019, and compared it to the carrying value of our net assets. Since the carrying value of our net assets exceeded our market capitalization and after considering various economic, industry, and company-specific factors, Company management determined that it was more likely than not that the fair value of the Company’s net assets was less than its carrying amount. As a result of our qualitative assessment, we proceeded to perform our quantitative goodwill impairment analysis, where we used an independent valuation specialist to assist us in determining the fair value of our net assets. In this impairment analysis, the estimated fair value of our net assets was determined utilizing market and income-based approaches. Determining fair value in this analysis required significant judgment, including judgments about appropriate comparable companies, appropriate discount rates and our estimated future cash flows, which are subject to change. As a result of our quantitative evaluation, we recorded a goodwill impairment charge of $10.0 million during the third quarter of 2019. A summary of changes in the Company’s goodwill during the nine months ended September 30, 2019 is as follows (in millions): Goodwill, net December 31, 2018 $ 10,039 Impairments (10,039) September 30, 2019 $ —

Credit Facility

Credit Facility	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Credit Facility	Credit Facility We have a senior secured revolving credit agreement the ("Amended Credit Agreement") with JP Morgan Chase Bank, N.A (the "Lender") with an aggregate commitment of $30 million, subject to collateral availability. We also have a right to request from the Lender, on an uncommitted basis, an increase of up to $20 million on the aggregate commitment (which could potentially increase the commitment amount to $50 million). On August 31, 2017, we amended and renewed the Amended Credit Agreement, extending the maturity date to December 31, 2020. No other material revisions were made to the credit facility. Borrowing Base . At any time before the maturity of the Amended Credit Agreement, we may draw, repay and re-borrow amounts available under the borrowing base up to the maximum aggregate availability discussed above. Generally, the borrowing base equals the sum of (a) 80% of our eligible accounts receivable plus (b) 50% of the book value of our eligible general inventory (not to exceed 50% of the commitment amount at the time) plus (c) 75% of the book value of our eligible equipment inventory. The Lender may adjust the borrowing base components if material deviations in the collateral are discovered in future audits of the collateral. We had $29.5 million borrowing base availability at September 30, 2019 under the terms of our Amended Credit Agreement. Interest and Fees . Under the terms of the Amended Credit Agreement, we have the option of selecting the applicable variable rate for each revolving loan, or portion thereof, of either (a) LIBOR multiplied by the Statutory Reserve Rate (as defined in the Amended Credit Agreement), with respect to this rate, for Eurocurrency funding, plus the Applicable Margin (“LIBOR-based”), or (b) CB Floating Rate, which is the Lender's Prime Rate less the Applicable Margin; provided, however, that no more than three LIBOR-based borrowings under the agreement may be outstanding at any one time. For purposes of the LIBOR-based interest rate, the Applicable Margin is 1.50%. For purposes of the CB Floating Rate, the Applicable Margin is 1.50%. For the nine month period ended September 30, 2019, our weighted average interest rate was 3.38%. Accrued interest is payable monthly on outstanding principal amounts, provided that accrued interest on LIBOR-based loans is payable at the end of each interest period, but in no event less frequently than quarterly. In addition, fees and expenses are payable in connection with our requests for letters of credit (generally equal to the Applicable Margin for LIBOR-related borrowings multiplied by the face amount of the requested letter of credit) and administrative and legal costs. Maturity . The maturity date of the Amended Credit Agreement is December 31, 2020, at which time all amounts borrowed under the agreement will be due and outstanding letters of credit must be cash collateralized. The agreement may be terminated early upon our request or the occurrence of an event of default. Security . The obligations under the Amended Credit Agreement are secured by a first priority lien on all of our inventory and accounts and leases receivables, along with a first priority lien on a variable number of our leased compressor equipment the book value of which must be maintained at a minimum of 2.00 to 1.00 commitment coverage ratio (such ratio being equal to (i) the amount of the borrowing base as of such date to (ii) the amount of the commitment as of such date). Covenants. The Amended Credit Agreement contains customary representations and warranties, as well as covenants which, among other things, limit our ability to incur additional indebtedness and liens; enter into transactions with affiliates; make acquisitions in excess of certain amounts; pay dividends; redeem or repurchase capital stock or senior notes; make investments or loans; make negative pledges; consolidate, merge or effect asset sales; or change the nature of our business. In addition, we also have certain financial covenants that require us to maintain on a consolidated basis a leverage ratio less than or equal to 2.50 to 1.00 as of the last day of each fiscal quarter. Events of Default and Acceleration. The Amended Credit Agreement contains customary events of default for credit facilities of this size and type, and includes, without limitation, payment defaults; defaults in performance of covenants or other agreements contained in the loan documents; inaccuracies in representations and warranties; certain defaults, termination events or similar events; certain defaults with respect to any other Company indebtedness in excess of $50,000; certain bankruptcy or insolvency events; the rendering of certain judgments in excess of $150,000; certain ERISA events; certain change in control events and the defectiveness of any liens under the secured revolving credit facility. Obligations under the Amended Credit Agreement may be accelerated upon the occurrence of an event of default. As of September 30, 2019, we were in compliance with all covenants in our Amended Credit Agreement. A default under our Credit Agreement could trigger the acceleration of our bank debt so that it is immediately due and payable. Such default would likely limit our ability to access other credit. At September 30, 2019 and December 31, 2018, our outstanding balance on the line of credit was $417,000.

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	Leases The Company adopted the new lease standard on January 1, 2019 using the modified retrospective transition method. Prior periods were not retrospectively adjusted and continue to be reported under the accounting standards in effect for those periods. The Company elected the package of practical expedients permitted under the transition guidance within the new lease standard, which among other things, allowed the company to continue to account for existing leases based on the historical lease classification. The Company also elected the practical expedients to exclude right-of-use ("ROU") assets and lease liabilities for leases with an initial term of 12 months or less from the balance sheet, and to combine lease and non-lease components for property leases, which primarily relate to ancillary expenses such as common area maintenance charges and management fees. The Company determines if an arrangement is a lease at inception by assessing whether it conveys the right to control the use of an identified asset for a period of time in exchange for consideration. The Company’s leases are primarily related to property leases for its field offices. The Company's leases have remaining lease terms of one The Company's lease agreements do not contain any contingent rental payments, material residual guarantees or material restrictive covenants. ROU assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. As substantially all of the Company's leases do not provide an implicit rate, the Company uses its incremental borrowing rate to determine the present value of lease payments. Based on the present value of lease payments for the Company's existing leases, the Company recorded net lease assets and lease liabilities of approximately $451,000, respectively, upon adoption. The Company had no finance leases. The new lease standard did not materially impact the Company's consolidated statements of operations and had no impact on the Company's consolidated statements of cash flows. The impact of the new lease standard on the September 30, 2019 consolidated balance sheet was as follows: Classification on the Condensed Consolidated Balance Sheet September 30, 2019 (in thousands, except years) Operating lease assets Right of use assets-operating leases $ 447 Current lease liabilities Current operating leases $ 107 Noncurrent lease liabilities Long-term operating leases 340 Total lease liabilities $ 447 Weighted average remaining lease term in years 2.9 Implicit Rate 3.8 % Operating lease costs are recognized on a straight-line basis over the lease term. Total operating lease costs for the nine months ended September 30, 2019 was approximately $426,000, which included approximately $277,000 related to short-term lease costs. September 30, 2019 (in thousands) Cash paid for amounts included in the measurement of lease liabilities Operating lease cost (1) $ 149 (1) Lease costs are classified on the condensed consolidated statements of income in cost of sales, cost of compressors and selling, general and administrative expenses. The following table shows the future maturities of lease liabilities: Years Ending December 31, Lease Liabilities (in thousands) 2019 (excluding the nine months ended September 30, 2019) $ 31 2020 116 2021 95 2022 43 2023 35 Thereafter 190 Total lease payments 510 Less: Imputed interest 63 Total $ 447 As previously disclosed on Form 10-K and under the previous lease standard (Topic 840), future minimum obligations under lease commitments in effect at December 31, 2018 as follows: Operating Leases (in thousands) 2019 $ 298 2020 118 2021 97 2022 44 2023 35 Thereafter 15 Total $ 607

(Loss) Earnings per Share

(Loss) Earnings per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
(Loss) Earnings per Share	(Loss) Earnings per Share The following table reconciles the numerators and denominators of the basic and diluted (loss) earnings per share computation (in thousands, except per share data) : Three months ended Nine months ended September 30, September 30, 2019 2018 2019 2018 Numerator: Net (loss) income $ (12,232) $ 236 $ (11,302) $ 708 Denominator for basic (loss) income per common share: Weighted average common shares outstanding 13,137 12,977 13,112 12,953 Denominator for diluted (loss) earnings per share: Weighted average common shares outstanding 13,137 12,977 13,112 12,953 Dilutive effect of stock options and restricted stock — 277 — 275 Diluted weighted average shares 13,137 13,254 13,112 13,228 (Loss) Earnings per common share: Basic $ (0.93) $ 0.02 $ (0.86) $ 0.05 Diluted $ (0.93) $ 0.02 $ (0.86) $ 0.05 In the three and nine months ended September 30, 2019, restricted stock and stock options were not included in the computation of diluted loss per share due to their antidilutive effect. In the three months ended September 30, 2018, options to purchase 126,334 shares of common stock with exercise prices ranging from $22.90 to $33.36 were not included in the computation of diluted earnings per share, due to their antidilutive effect. In the nine months ended September 30, 2018, options to purchase 82,167 shares of common stock with exercise prices ranging from $28.15 to $33.36 were not included in the computation of diluted earnings per share, due to their antidilutive effect.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segment Information	Segment Information ASC 280-10-50, “Operating Segments", defines the characteristics of an operating segment as: a) being engaged in business activity from which it may earn revenue and incur expenses, b) being reviewed by the Company's chief operating decision maker (CODM) for decisions about resources to be allocated and assess its performance and c) having discrete financial information. Although we look at our products to analyze the nature of our revenue, other financial information, such as certain costs and expenses, net income and EBITDA are not captured or analyzed by these categories. Our CODM does not make resource allocation decisions or access the performance of the business based on these categories, but rather in the aggregate. Based on this, management believes that it operates in one business segment. In their analysis of product lines as potential operating segments, management also considered ASC 280-10-50-11, “Aggregation Criteria”, which allows for the aggregation of operating segments if the segments have similar economic characteristics and if the segments are similar in each of the following areas: • The nature of the products and services; • The nature of the production processes; • The type or class of customer for their products and services; • The methods used to distribute their products or provide their services; and • The nature of the regulatory environment, if applicable. We are engaged in the business of designing and manufacturing compressors and flares. Our compressors and flares are sold and rented to our customers. In addition, we provide service and maintenance on compressors in our fleet and to third parties. These business activities are similar in all geographic areas. Our manufacturing process is essentially the same for the entire Company and is performed in-house at our facilities in Midland, Texas and Tulsa, Oklahoma. Our customers primarily consist of entities in the business of producing natural gas and crude oil. The maintenance and service of our products is consistent across the entire Company and is performed via an internal fleet of vehicles. The regulatory environment is similar in every jurisdiction in that the most impacting regulations and practices are the result of federal energy policy. In addition, the economic characteristics of each customer arrangement are similar in that we maintain policies at the corporate level. For the three months ended September 30, 2019 (in thousands): Rental Sales Service & Maintenance Corporate Total Revenue $ 14,434 $ 5,877 $ 541 $ — $ 20,852 Operating costs and corporate expenses 6,300 4,390 164 18,697 29,551 Inventory Allowance 987 2,363 — — 3,350 Retirement of Rental Equipment 1,512 — — — 1,512 Total other income, net — — — 89 89 Income before provision for income taxes $ 5,635 $ (876) $ 377 $ (18,608) $ (13,472) For the three months ended September 30, 2018 (in thousands): Rental Sales Service & Maintenance Corporate Total Revenue $ 12,039 $ 3,947 $ 410 $ — $ 16,396 Operating costs and corporate expenses 5,363 3,081 107 7,889 16,440 Total other income, net — — — 180 180 Income before provision for income taxes $ 6,676 $ 866 $ 303 $ (7,709) $ 136 For the nine months ended September 30, 2019 (in thousands): Rental Sales Service & Maintenance Corporate Total Revenue $ 41,393 $ 15,816 $ 1,529 $ — $ 58,738 Operating costs and expenses 18,544 12,508 470 35,113 66,635 Inventory Allowance 987 2,363 — — 3,350 Retirement of Rental Equipment 1,512 — — — 1,512 Total other income, net — — — 567 567 Income before provision for income taxes $ 20,350 $ 945 $ 1,059 $ (34,546) $ (12,192) For the nine months ended September 30, 2018 (in thousands: Rental Sales Service & Maintenance Corporate Total Revenue $ 34,937 $ 13,328 $ 1,053 $ — $ 49,318 Operating costs and expenses 15,262 10,196 273 23,055 48,786 Total other income, net — — — 179 179 Income before provision for income taxes $ 19,675 $ 3,132 $ 780 $ (22,876) $ 711

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies From time to time, we are a party to various legal proceedings in the ordinary course of our business. While management is unable to predict the ultimate outcome of these actions, it believes that any ultimate liability arising from these actions will not have a material adverse effect on our financial position, results of operations or cash flow. We are not currently a party to any material legal proceedings, and we are not aware of any threatened material litigation. As of September 30, 2019, the Company has a remaining contractual obligation related to the construction of a new corporate office of approximately $375,000, to be financed by cash on hand. Construction of a new office began in late 2017 and is expected to be completed in 2019. Stock Repurchase Program

Related Party

Related Party	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Related Party	Related Party In 2016, we entered into a joint venture partnership, N-G, LLC (‘N-G”), with Genis Holdings, LLC (“Genis”) to explore new technologies for wellhead compression. NGS and Genis both share 50% ownership of N-G. In 2018, we ordered some compressor packages from Genis, totaling $1.0 million. The compressors were completed and delivered during the first quarter of 2019. As of September 30, 2019, the units were paid in full and reclassified from prepaids and are included in rental equipment on the consolidated balance sheet.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Accounting	These notes apply to the unaudited condensed consolidated financial statements of Natural Gas Services Group, Inc. a Colorado corporation (the "Company", “NGSG”, "Natural Gas Services Group", "we" or "our"). The accompanying unaudited condensed consolidated financial statements include the accounts of the Company, its subsidiary, NGSG Properties, LLC and the rabbi trust associated with the Company's deferred compensation plan (see Note 5). All significant intercompany accounts and transactions for the periods presented have been eliminated in consolidation. These financial statements include all adjustments, consisting of only normal recurring adjustments, which are necessary to make our financial position at September 30, 2019 and the results of our operations for the three and nine months ended September 30, 2019 and 2018 not misleading. As permitted by the rules and regulations of the Securities and Exchange Commission (SEC), the accompanying condensed consolidated financial statements do not include all disclosures normally required by generally accepted accounting principles in the United States of America (GAAP). These financial statements should be read in conjunction with the financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2018 on file with the SEC. In our opinion, the condensed consolidated financial statements are a fair presentation of the financial position, results of operations, changes in stockholders' equity and cash flows for the periods presented. The results of operations for the three and nine months ended September 30, 2019 are not necessarily indicative of the results of operations to be expected for the full fiscal year ending December 31, 2019.
Revenue Recognition Policy	Revenue Recognition Policy The Company adopted ASC 606, Revenue from Contracts with Customers ("ASC 606") on January 1, 2018. As a result, the Company has changed its accounting policy for revenue recognition as detailed below. The Company applied ASC 606 using the cumulative effect method. We had no significant changes in our recognition of revenue at adoption and our review of all open revenue from contracts with customers on January 1, 2018 indicated we had no adjustment to be made. If an adjustment had been needed, we would have recognized the cumulative effect of initially applying ASC 606 with an adjustment to the opening balance of equity at January 1, 2018. Revenue is measured based on a consideration specified in a customer’s contract, excluding any sale incentives and taxes collected on behalf of third parties (i.e. sales and property taxes). We recognize revenue once our performance obligation has been satisfied and control over a product or service has transferred to the customer. Shipping and handling costs incurred are accounted for as fulfillment costs and are included in cost of revenues in our condensed consolidated income statement. Nature of Goods and Services The following is a description of principal activities from which the Company generates its revenue: Rental Revenue. The Company generates revenue from renting compressors and flare systems to our customers. These contracts may also include a fee for servicing the compressor or flare during the rental contract. Our rental contracts generally range from six to 60 months, with our larger horsepower compressors having longer minimum contract terms. Our rental revenue is recognized over time, with equal monthly payments over the term of the contract. After the term of a contract has expired, a customer may renew their contract or continue renting on a monthly basis thereafter. In accordance ASC 842 – Leases, we have applied the practical expedient ASC 842-10-15-42A, which allows the Company to combine lease and non-lease components. Sales Revenue. The Company generates revenue by the sale of custom/fabricated compressors, flare systems, and parts, as well as, exchange/rebuilding customer owned compressors and sale of used rental equipment. Custom/fabricated compressors and flare systems - The Company designs and fabricates compressors and flares based on the customer’s specifications outlined in their contract. Though the equipment being built is customized by the customer, control under these contracts does not pass to the customer until the compressor or flare package is complete and shipped, or in accordance with a bill and hold arrangements the customer accepts title and assumes the risk and rewards of ownership. We request some of our customers to make progressive payments as the product is being built; these payments are recorded as a contract liability on the Deferred Income line on the condensed consolidated balance sheet until control has been transferred. These contracts also may include an assurance warranty clause to guarantee the product is free from defects in material and workmanship for a set duration of time; this is a standard industry practice and is not considered a performance obligation. From time to time, upon the customer’s written request, we recognize revenue when manufacturing is complete and the equipment is ready for shipment. At the customer’s request, we will bill the customer upon completing all performance obligations, but before shipment. The customer will formally request that we ship the equipment per their direction from our manufacturing facility at a later specified date and that we segregate the equipment from our finished goods, such that they are not available to fill other orders. Per the customer’s agreement change of control is passed to the customer once the equipment is complete and ready for shipment. We have operated using bill and hold agreements with certain customers for many years, with consistent satisfactory results for both the customer and us. The credit terms on these agreements are consistent with the credit terms on all other sales. All control is shouldered by the customer and there are no exceptions to the customer’s commitment to accept and pay for the manufactured equipment. Revenues recognized related to bill and hold arrangements for the nine months ended September 30, 2019 was approximately $9.4 million. Parts - Revenue is recognized after the customer obtains control of the parts. Control is passed either by the customer taking physical possession or the parts being shipped. The amount of revenue recognized is not adjusted for expected returns, as our historical part returns have been de minimis. Exchange or rebuilding customer owned compressors - Based on the contract, the Company will either exchange a new/rebuilt compressor for the customer’s malfunctioning compressor or rebuild the customer’s compressor. Revenue is recognized after control of the replacement compressor has transferred to the customer by physical delivery, delivery and installment or shipment of the compressor. Used compressors or flares - From time to time, a customer may request to purchase a used compressor or flare out of our rental fleet. Revenue from the sale of rental equipment is recognized when the control has passed to the customer, when the customer has taken physical possession or the equipment has been shipped. Service and Maintenance Revenue . The Company provides routine or call-out services on customer owned equipment. Revenue is recognized after services in the contract are rendered. Payment terms for sales revenue and service and maintenance revenue discussed above are generally 30 to 60 days although terms for specific customers can vary. Also, transaction prices are not subject to variable consideration constraints.
Contract Costs	Contract Costs
Leases	Leases On January 1, 2019, we adopted ASC 842, Leases ("ASC 842") and all the related amendments using the modified retrospective method. We recognized the cumulative effect of initially applying the new lease standard and had no adjustments to retained earnings. The comparative information has not been restated and continues to be reported under the lease accounting standard in effect for those periods. We do not expect the adoption of the new lease standard to have a material impact to our net income on an ongoing basis. The new lease standard requires all leases to be reported on the balance sheet as right-of-use assets and lease obligations. We elected the practical expedients permitted under the transition guidance of the new standard that retained the lease classification and initial direct costs for any leases that existed prior to adoption of the standard. We did not reassess whether any contracts or land easements entered into prior to adoption are leases or contain leases. The cumulative effect of the changes made to our consolidated balance sheet at January 1, 2019, for the adoption of ASU 2016-02, Leases, was as follows (in thousands): Balance at December 31, 2018 Adjustments due to ASU 2016-02 Balance at January 1, 2019 Balance Sheet Assets Right of use assets $ — $ 451 $ 451 Liabilities Current portion of operating leases $ — $ 126 $ 126 Long term portion of operating leases — 325 325 Total lease liabilities $ — $ 451 $ 451 The Company, as a lessee, applies the practical expedient in ASC 842-10-15-37, and does not separate non-lease components from lease components, therefore, accounting for each separate lease component and its associated non-lease component, as a single lease component. The Company, as a lessor, applies the practical expedient in ASC 842-10-15-42A, in leases that contain the same timing and pattern of transfer for lease and non-lease components and are deemed operating leases, the lessor is not required to separate non-lease components from lease components. Therefore, on any lease that meets these qualifications we have chosen to account for each separate lease component and its associated non-lease component, as a single lease component. The Company applies the practical expedient in ASC 842-20-25-2, to recognize the lease payments in profit or loss on a straight-line basis over the lease term and variable lease payments in the period in which the obligation for those payments is incurred for leases with terms of 12 months or less.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Our financial instruments consist principally of cash and cash equivalents, accounts receivable, accounts payable, deferred compensation plan (cash portion) and our line of credit. Pursuant to ASC 820 (Accounting Standards Codification), the fair value of our cash equivalents is determined based on “Level 1” inputs, which consist of quoted prices in active markets for identical assets. We believe that the recorded values of all of our other financial instruments approximate their fair values because of their nature (variable rate debt) and relatively short maturity dates or durations.
Income Taxes	Income Taxes As part of the process of preparing our financial statements, we are required to estimate our federal income taxes as well as income taxes in each of the states in which we operate. We use an estimated annual effective tax rate for purposes of determining the income tax provision during interim reporting periods. In calculating our estimated annual effective tax rate, we consider forecasted annual pre-tax income and estimated permanent book versus tax differences, as well as tax credits. Adjustments to the effective tax rate and estimate will occur as information and assumptions change.This process involves us estimating our actual current tax exposure together with assessing temporary differences resulting from differing treatment of items for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included in our consolidated balance sheet. We must then assess the likelihood that our deferred tax assets will be recovered from future taxable income and, to the extent we believe that recovery is not probable, we must establish a valuation allowance. To the extent we establish a valuation allowance or increase this allowance in a period, we must include an expense in the tax provision in the statement of operations. Significant management judgment is required in determining our provision for income taxes, our deferred tax assets and liabilities and any valuation allowance recorded against our net deferred tax assets. We currently have no valuation allowance and fully expect to utilize all of our deferred tax assets. ASC Topic 740 prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. In order to record any financial statement benefit, we are required to determine, based on technical merits of the position, whether it is more likely than not (a likelihood of more than 50 percent) that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes. If that step is satisfied, then we must measure the tax position to determine the amount of benefit to recognize in the financial statements. The tax position is measured at the largest amount of the benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement. Our policy regarding income tax interest and penalties is to expense those items as other expense. During the fourth quarter of 2018, the Company discovered a potential uncertain tax position attributable to the deductibility of certain executive compensation expense for federal income tax purposes aggregating approximately $168,000, $149,000 and $230,000 for the years ended December 31, 2017, 2016 and 2015, respectively. As a result, in accordance with ASC Topic 740, during the fourth quarter of 2018, the Company recorded a tax adjustment of $547,000 and accrued penalty and interest expense of $55,000 attributable to the uncertain tax position. The Company's management determined the effect of the potential uncertain tax position on previously reported results of operations for the years ended December 31, 2017 and 2016 was not material. As of September 30, 2019, the Company has filed an amended tax return for the year ended 2015 and has recognized certain offsetting deductions thus reducing our uncertain tax position reserve for 2015, 2016 and 2017. Accrued interest and penalties at September 30, 2019 related to 2016 and 2017 uncertain tax position was approximately $23,000. The Company plans on amending it's 2016 and 2017 filed federal income tax returns and is still in the process of analyzing certain offsetting deductions to reduce the uncertain tax position reserve.
Reclassification of Prior Period Balances	Reclassification of Prior Period Balances Certain reclassifications have been made to prior period amounts, due to our adoption of ASC 842, to conform to the current-year presentation. These reclassifications had no effect on the financial statements.
Segment Information	ASC 280-10-50, “Operating Segments", defines the characteristics of an operating segment as: a) being engaged in business activity from which it may earn revenue and incur expenses, b) being reviewed by the Company's chief operating decision maker (CODM) for decisions about resources to be allocated and assess its performance and c) having discrete financial information. Although we look at our products to analyze the nature of our revenue, other financial information, such as certain costs and expenses, net income and EBITDA are not captured or analyzed by these categories. Our CODM does not make resource allocation decisions or access the performance of the business based on these categories, but rather in the aggregate. Based on this, management believes that it operates in one business segment. In their analysis of product lines as potential operating segments, management also considered ASC 280-10-50-11, “Aggregation Criteria”, which allows for the aggregation of operating segments if the segments have similar economic characteristics and if the segments are similar in each of the following areas: • The nature of the products and services; • The nature of the production processes; • The type or class of customer for their products and services; • The methods used to distribute their products or provide their services; and • The nature of the regulatory environment, if applicable. We are engaged in the business of designing and manufacturing compressors and flares. Our compressors and flares are sold and rented to our customers. In addition, we provide service and maintenance on compressors in our fleet and to third parties. These business activities are similar in all geographic areas. Our manufacturing process is essentially the same for the entire Company and is performed in-house at our facilities in Midland, Texas and Tulsa, Oklahoma. Our customers primarily consist of entities in the business of producing natural gas and crude oil. The maintenance and service of our products is consistent across the entire Company and is performed via an internal fleet of vehicles. The regulatory environment is similar in every jurisdiction in that the most impacting regulations and practices are the result of federal energy policy. In addition, the economic characteristics of each customer arrangement are similar in that we maintain policies at the corporate level.

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Disaggregation of Revenue	The following table shows the Company's revenue disaggregated by product or service type for the three and nine months ended September 30, 2019 and 2018: Three months ended September 30, Nine months ended September 30, (in thousands) (in thousands) 2019 2018 2019 2018 Compressors - sales $ 4,703 $ 2,891 $ 12,199 $ 9,454 Flares - sales 243 336 783 1,827 Other (Parts/Rebuilds) - sales 931 720 2,834 2,047 Service and maintenance 541 410 1,529 1,053 Total revenue from contracts with customers 6,418 4,357 17,345 14,381 Add: non-ASC 606 rental revenue 14,434 12,039 41,393 34,937 Total revenue $ 20,852 $ 16,396 $ 58,738 $ 49,318
Schedule of Contract with Customer, Asset and Liability	As of September 30, 2019 and December 31, 2018, we had the following receivables and deferred income from contracts with customers: September 30, 2019 December 31, 2018 (in thousands) Accounts Receivable Accounts receivable - contracts with customers $ 4,038 $ 2,250 Accounts receivable - non-ASC 606 7,511 5,260 Total Accounts Receivable $ 11,549 $ 7,510 Less: Allowance for doubtful accounts (325) (291) Total Accounts Receivable, net $ 11,224 $ 7,219 Deferred income $ 81 $ 81
Cumulative Effect of Changes from Adoption of ASU	The cumulative effect of the changes made to our consolidated balance sheet at January 1, 2019, for the adoption of ASU 2016-02, Leases, was as follows (in thousands): Balance at December 31, 2018 Adjustments due to ASU 2016-02 Balance at January 1, 2019 Balance Sheet Assets Right of use assets $ — $ 451 $ 451 Liabilities Current portion of operating leases $ — $ 126 $ 126 Long term portion of operating leases — 325 325 Total lease liabilities $ — $ 451 $ 451
Reconciliation of Uncertain Tax Positions	A reconciliation of uncertain tax positions of the beginning and ending amount of uncertain tax positions is as follows (in thousands): Balance at January 1, 2019 $ 578 Additions based on tax positions related to current year — Reductions for tax positions of prior years (319) Balance at September 30, 2019 $ 259

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Summary of Option Activity	A summary of option activity under our 1998 Stock Option Plan as of December 31, 2018, and changes during the nine months ended September 30, 2019 is presented below. Number of Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (years) Aggregate Intrinsic Value (in thousands) Outstanding, December 31, 2018 283,686 $ 20.46 3.58 $ 434 Exercised (56,352) 8.97 — 474 Canceled/Forfeited (3,000) 27.91 — — Outstanding, September 30, 2019 224,334 $ 23.25 3.67 $ — Exercisable, September 30, 2019 213,901 $ 23.01 3.49 $ —
Summary of Stock Options Outstanding	The following table summarizes information about our stock options outstanding at September 30, 2019: Range of Exercise Prices Options Outstanding Options Exercisable Shares Weighted Average Remaining Contractual Life (years) Weighted Average Exercise Price Shares Weighted Average Exercise Price $0.01-15.70 8,500 2.32 $ 14.89 8,500 $ 14.89 $15.71-17.81 42,000 0.82 17.54 42,000 17.54 $17.82-20.48 50,500 1.59 19.43 50,500 19.43 $20.49-33.36 123,334 5.59 27.33 112,901 27.26 224,334 3.67 $ 23.25 213,901 $ 23.01
Status of Unvested Stock Options	The summary of the status of our unvested stock options as of December 31, 2018 and changes during the nine months ended September 30, 2019 is presented below. Unvested stock options: Shares Weighted Average Grant Date Fair Value Per Share Unvested at December 31, 2018 20,865 $ 11.93 Vested (10,432) 11.93 Unvested at September 30, 2019 10,433 $ 11.93

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2019
Inventory Disclosure [Abstract]
Schedule of Inventory	Our inventory, net of allowance for obsolescence of $3.4 million at September 30, 2019 and $19,000 December 31, 2018 consisted of the following amounts: September 30, 2019 December 31, 2018 (in thousands) Raw materials - current $ 23,893 $ 26,152 Raw materials - long term, net 540 3,980 Finished Goods 1,022 1,022 Work in process 5,374 3,800 $ 30,829 $ 34,954

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Changes in Goodwill	A summary of changes in the Company’s goodwill during the nine months ended September 30, 2019 is as follows (in millions): Goodwill, net December 31, 2018 $ 10,039 Impairments (10,039) September 30, 2019 $ —

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Schedule of Balance Sheet Impact	The impact of the new lease standard on the September 30, 2019 consolidated balance sheet was as follows: Classification on the Condensed Consolidated Balance Sheet September 30, 2019 (in thousands, except years) Operating lease assets Right of use assets-operating leases $ 447 Current lease liabilities Current operating leases $ 107 Noncurrent lease liabilities Long-term operating leases 340 Total lease liabilities $ 447 Weighted average remaining lease term in years 2.9 Implicit Rate 3.8 %
Schedule of Cash Flow Impact	September 30, 2019 (in thousands) Cash paid for amounts included in the measurement of lease liabilities Operating lease cost (1) $ 149 (1) Lease costs are classified on the condensed consolidated statements of income in cost of sales, cost of compressors and selling, general and administrative expenses.
Schedule of Future Maturities of Lease Liabilities	The following table shows the future maturities of lease liabilities: Years Ending December 31, Lease Liabilities (in thousands) 2019 (excluding the nine months ended September 30, 2019) $ 31 2020 116 2021 95 2022 43 2023 35 Thereafter 190 Total lease payments 510 Less: Imputed interest 63 Total $ 447
Schedule of Future Minimum Obligations Under Lease Commitments	As previously disclosed on Form 10-K and under the previous lease standard (Topic 840), future minimum obligations under lease commitments in effect at December 31, 2018 as follows: Operating Leases (in thousands) 2019 $ 298 2020 118 2021 97 2022 44 2023 35 Thereafter 15 Total $ 607

(Loss) Earnings per Share (Tabl

(Loss) Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table reconciles the numerators and denominators of the basic and diluted (loss) earnings per share computation (in thousands, except per share data) : Three months ended Nine months ended September 30, September 30, 2019 2018 2019 2018 Numerator: Net (loss) income $ (12,232) $ 236 $ (11,302) $ 708 Denominator for basic (loss) income per common share: Weighted average common shares outstanding 13,137 12,977 13,112 12,953 Denominator for diluted (loss) earnings per share: Weighted average common shares outstanding 13,137 12,977 13,112 12,953 Dilutive effect of stock options and restricted stock — 277 — 275 Diluted weighted average shares 13,137 13,254 13,112 13,228 (Loss) Earnings per common share: Basic $ (0.93) $ 0.02 $ (0.86) $ 0.05 Diluted $ (0.93) $ 0.02 $ (0.86) $ 0.05

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Schedule of Segment Reporting Information	We are engaged in the business of designing and manufacturing compressors and flares. Our compressors and flares are sold and rented to our customers. In addition, we provide service and maintenance on compressors in our fleet and to third parties. These business activities are similar in all geographic areas. Our manufacturing process is essentially the same for the entire Company and is performed in-house at our facilities in Midland, Texas and Tulsa, Oklahoma. Our customers primarily consist of entities in the business of producing natural gas and crude oil. The maintenance and service of our products is consistent across the entire Company and is performed via an internal fleet of vehicles. The regulatory environment is similar in every jurisdiction in that the most impacting regulations and practices are the result of federal energy policy. In addition, the economic characteristics of each customer arrangement are similar in that we maintain policies at the corporate level. For the three months ended September 30, 2019 (in thousands): Rental Sales Service & Maintenance Corporate Total Revenue $ 14,434 $ 5,877 $ 541 $ — $ 20,852 Operating costs and corporate expenses 6,300 4,390 164 18,697 29,551 Inventory Allowance 987 2,363 — — 3,350 Retirement of Rental Equipment 1,512 — — — 1,512 Total other income, net — — — 89 89 Income before provision for income taxes $ 5,635 $ (876) $ 377 $ (18,608) $ (13,472) For the three months ended September 30, 2018 (in thousands): Rental Sales Service & Maintenance Corporate Total Revenue $ 12,039 $ 3,947 $ 410 $ — $ 16,396 Operating costs and corporate expenses 5,363 3,081 107 7,889 16,440 Total other income, net — — — 180 180 Income before provision for income taxes $ 6,676 $ 866 $ 303 $ (7,709) $ 136 For the nine months ended September 30, 2019 (in thousands): Rental Sales Service & Maintenance Corporate Total Revenue $ 41,393 $ 15,816 $ 1,529 $ — $ 58,738 Operating costs and expenses 18,544 12,508 470 35,113 66,635 Inventory Allowance 987 2,363 — — 3,350 Retirement of Rental Equipment 1,512 — — — 1,512 Total other income, net — — — 567 567 Income before provision for income taxes $ 20,350 $ 945 $ 1,059 $ (34,546) $ (12,192) For the nine months ended September 30, 2018 (in thousands: Rental Sales Service & Maintenance Corporate Total Revenue $ 34,937 $ 13,328 $ 1,053 $ — $ 49,318 Operating costs and expenses 15,262 10,196 273 23,055 48,786 Total other income, net — — — 179 179 Income before provision for income taxes $ 19,675 $ 3,132 $ 780 $ (22,876) $ 711

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue from External Customer [Line Items]
Revenue	$ 20,852		$ 16,396	$ 58,738	$ 49,318
Additions to tax positions of prior years		$ 547
Income tax penalties and interest accrued	$ 23	55		23
Bill and Hold Arrangement
Revenue from External Customer [Line Items]
Revenue				$ 9,400
Minimum
Revenue from External Customer [Line Items]
Amortization period of capitalized contract costs	1 year			1 year
Tax Year 2017
Revenue from External Customer [Line Items]
Additions to tax positions of prior years		168
Tax Year 2016
Revenue from External Customer [Line Items]
Additions to tax positions of prior years		149
Tax Year 2015
Revenue from External Customer [Line Items]
Additions to tax positions of prior years		$ 230

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 6,418	$ 4,357	$ 17,345	$ 14,381
Add: non-ASC 606 rental revenue	14,434	12,039	41,393	34,937
Revenue	20,852	16,396	58,738	49,318
Compressors - sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	4,703	2,891	12,199	9,454
Flares - sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	243	336	783	1,827
Other (Parts/Rebuilds) - sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	931	720	2,834	2,047
Service and maintenance
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	541	410	1,529	1,053
Revenue	$ 541	$ 410	$ 1,529	$ 1,053

Basis of Presentation and Sum_6

Basis of Presentation and Summary of Significant Accounting Policies (Contract Balances) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Accounts Receivable
Accounts receivable - contracts with customers	$ 4,038	$ 2,250
Accounts receivable - non-ASC 606	7,511	5,260
Total Accounts Receivable	11,549	7,510
Less: Allowance for doubtful accounts	(325)	(291)
Total Accounts Receivable, net	11,224	7,219
Deferred income	81	81
Revenue recognized	$ 47	$ 176

Basis of Presentation and Sum_7

Basis of Presentation and Summary of Significant Accounting Policies (Cumulative Effect of Changes from Adoption of ASU) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Right of use assets	$ 447	$ 451	$ 0
Liabilities
Current portion of operating leases	107	126	0
Long term portion of operating leases	340	325	0
Total lease liabilities	$ 447	451	$ 0
Accounting Standards Update 2016-02
Assets
Right of use assets		451
Liabilities
Current portion of operating leases		126
Long term portion of operating leases		325
Total lease liabilities		$ 451

Basis of Presentation and Sum_8

Basis of Presentation and Summary of Significant Accounting Policies (Reconciliation of Uncertain Tax Positions) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Uncertain tax positions, beginning balance	$ 578
Additions based on tax positions related to current year	0
Reductions for tax positions of prior years	(319)
Uncertain tax positions, ending balance	$ 259

Stock-Based Compensation (Stock

Stock-Based Compensation (Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2019	Sep. 30, 2019
Number ofStock Options
Outstanding, beginning of period (in shares)	283,686	283,686
Exercised (in shares)		(56,352)
Canceled/Forfeited (in shares)		(3,000)
Outstanding, end of period (in shares)		224,334
Exercisable (in shares)		213,901
Weighted AverageExercise Price
Outstanding, beginning of period (in USD per share)	$ 20.46	$ 20.46
Exercised (in USD per share)		8.97
Canceled/Forfeited (in USD per share)		27.91
Outstanding, end of period (in USD per share)		23.25
Exercisable (in USD per share)		$ 23.01
Weighted Average Remaining Contractual Life (years)
Outstanding	3 years 6 months 29 days	3 years 8 months 1 day
Exercisable		3 years 5 months 26 days
Aggregate Intrinsic Value (in thousands)
Outstanding, beginning of period	$ 434	$ 434
Exercised		474
Canceled/Forfeited		0
Outstanding, end of period		0
Exercisable		$ 0

Stock-Based Compensation (Sto_2

Stock-Based Compensation (Stock Options Outstanding) (Details)	9 Months Ended
	Sep. 30, 2019$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, shares (in shares) | shares	224,334
Options outstanding, weighted average remaining contractual life (years)	3 years 8 months 1 day
Options outstanding, weighted average exercise price (in USD per share)	$ 23.25
Options exercisable, shares (in shares) | shares	213,901
Options exercisable, weighted average exercise price (in USD per share)	$ 23.01
$0.01-15.70
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, lower limit (in USD per share)	0.01
Range of exercise prices, upper limit (in USD per share)	$ 15.70
Options outstanding, shares (in shares) | shares	8,500
Options outstanding, weighted average remaining contractual life (years)	2 years 3 months 25 days
Options outstanding, weighted average exercise price (in USD per share)	$ 14.89
Options exercisable, shares (in shares) | shares	8,500
Options exercisable, weighted average exercise price (in USD per share)	$ 14.89
$15.71-17.81
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, lower limit (in USD per share)	15.71
Range of exercise prices, upper limit (in USD per share)	$ 17.81
Options outstanding, shares (in shares) | shares	42,000
Options outstanding, weighted average remaining contractual life (years)	9 months 25 days
Options outstanding, weighted average exercise price (in USD per share)	$ 17.54
Options exercisable, shares (in shares) | shares	42,000
Options exercisable, weighted average exercise price (in USD per share)	$ 17.54
$17.82-20.48
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, lower limit (in USD per share)	17.82
Range of exercise prices, upper limit (in USD per share)	$ 20.48
Options outstanding, shares (in shares) | shares	50,500
Options outstanding, weighted average remaining contractual life (years)	1 year 7 months 2 days
Options outstanding, weighted average exercise price (in USD per share)	$ 19.43
Options exercisable, shares (in shares) | shares	50,500
Options exercisable, weighted average exercise price (in USD per share)	$ 19.43
$20.49-33.36
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, lower limit (in USD per share)	20.49
Range of exercise prices, upper limit (in USD per share)	$ 33.36
Options outstanding, shares (in shares) | shares	123,334
Options outstanding, weighted average remaining contractual life (years)	5 years 7 months 2 days
Options outstanding, weighted average exercise price (in USD per share)	$ 27.33
Options exercisable, shares (in shares) | shares	112,901
Options exercisable, weighted average exercise price (in USD per share)	$ 27.26

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary of Unvested Stock Options) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Shares
Unvested, beginning of period (in shares)	20,865
Vested (in shares)	(10,432)
Unvested, end of period (in shares)	10,433
Weighted Average Grant Date Fair Value Per Share
Unvested, weighted average grant date fair value, beginning of period (in USD per share)	$ 11.93
Vested, weighted average grant date fair value (in USD per share)	11.93
Unvested, weighted average grant date fair value, end of period (in USD per share)	$ 11.93
Stock Options
Weighted Average Grant Date Fair Value Per Share
Unrecognized compensation cost related to unvested options	$ 46,105
Unrecognized compensation cost related to awards, weighted average period for recognition	1 year
Share-based compensation expense	$ 91,984	$ 127,055

Stock-Based Compensation (Restr

Stock-Based Compensation (Restricted Stock) (Details) - Restricted Stock - USD ($) $ in Millions	Mar. 29, 2019	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		$ 1.7	$ 1.6
Total unrecognized compensation expense		$ 4.3
Unrecognized compensation cost related to awards, vesting period		3 years
Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	131,674
Award vesting period	3 years
Chief Financial Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	20,000
Award vesting period	3 years
Vice President of Technical Services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	20,000
Award vesting period	3 years
Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)		23,136
Award vesting period		1 year

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Allowance for obsolescence	$ 3,371	$ 19
Raw materials - current	23,893	26,152
Raw materials - long term, net	540	3,980
Finished Goods	1,022	1,022
Work in process	5,374	3,800
Inventory, net	$ 30,829	$ 34,954

Inventory Allowance and Retir_2

Inventory Allowance and Retirement of Long-Lived Assets (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)compressor	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Impaired Assets to be Disposed of by Method Other than Sale [Line Items]
Inventory allowance	$ 3,350	$ 3,350	$ 0
Allowance for obsolescence	3,371	3,371		$ 19
Loss on retirement of rental equipment	$ 1,512	$ 1,512	$ 0
Rental Compressor Unit
Impaired Assets to be Disposed of by Method Other than Sale [Line Items]
Number of units retired | compressor		327
Rental Compressor Unit | Loss On Retirement of Rental Equipment
Impaired Assets to be Disposed of by Method Other than Sale [Line Items]
Loss on retirement of rental equipment		$ 1,500

Deferred Compensation Plan (Det

Deferred Compensation Plan (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Postemployment Benefits [Abstract]
Participant's maximum compensation deferral percentage	90.00%
Company owned life insurance	$ 1,400	$ 1,100
Gain (loss) on company owned life insurance	145	(15)
Deferred compensation obligation	$ 1,500	$ 1,200
Deferred restricted stock shares (in shares)	94,148	102,793
Deferred compensation arrangement with individual, shares issued (in shares)	80,604	33,834
Deferred compensation arrangement, fair value of shares issued	$ 1,700	$ 857

Goodwill (Narrative) (Details)

Goodwill (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment charge	$ 10,039	$ 0	$ 10,039	$ 0

Goodwill (Summary of Changes in

Goodwill (Summary of Changes in Goodwill) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Goodwill [Roll Forward]
Goodwill, beginning balance			$ 10,039
Impairments	$ (10,039)	$ 0	(10,039)	$ 0
Goodwill, ending balance	$ 0		$ 0

Credit Facility (Details)

Credit Facility (Details) - Revolving Credit Facility	9 Months Ended
	Sep. 30, 2019USD ($)loan	Dec. 31, 2018USD ($)
Line of Credit Facility [Line Items]
Aggregate credit agreement commitment	$ 30,000,000
Potential increase in borrowing capacity	20,000,000
Potential maximum borrowing capacity	$ 50,000,000
Borrowing base, component, % of eligible accounts receivable	80.00%
Borrowing base, component, % of eligible inventory	50.00%
Borrowing base, allowable share of total commitment amount attributable to inventory component	50.00%
Borrowing base, component, % of eligible equipment inventory	75.00%
Borrowing base amount available	$ 29,500,000
Weighted average interest rate	3.38%
Default trigger, certain defaults of other company indebtedness, amount	$ 50,000
Default trigger, rendering of certain judgments, amount	150,000
Line of credit balance	$ 417,000	$ 417,000
LIBOR Rate
Line of Credit Facility [Line Items]
Reference rate, number of allowable LIBOR-based borrowings outstanding | loan	3
Variable rate, applicable margin	1.50%
CB Floating Rate
Line of Credit Facility [Line Items]
Variable rate, applicable margin	1.50%
Minimum
Line of Credit Facility [Line Items]
Minimum commitment coverage ratio allowed	2
Maximum
Line of Credit Facility [Line Items]
Maximum leverage ratio allowed	2.50

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Right of use assets	$ 447	$ 451	$ 0
Operating lease, liability	447	451	$ 0
Lease costs	426
Short-term lease cost	$ 277
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Right of use assets		451
Operating lease, liability		$ 451
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	10 years

Leases (Balance Sheet Impact) (

Leases (Balance Sheet Impact) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Right of use assets	$ 447	$ 451	$ 0
Current operating leases	107	126	0
Long-term operating leases	340	325	0
Total lease liabilities	$ 447	$ 451	$ 0
Weighted average remaining lease term in years	2 years 10 months 24 days
Implicit Rate	3.80%

Leases (Cash Flow Impact) (Deta

Leases (Cash Flow Impact) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 149

Leases (Future Maturities of Le

Leases (Future Maturities of Lease Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
2019 (excluding the nine months ended September 30, 2019)	$ 31
2020	116
2021	95
2022	43
2023	35
Thereafter	190
Total lease payments	510
Less: Imputed interest	63
Operating lease, liability	$ 447	$ 451	$ 0

Leases (Future Minimum Obligati

Leases (Future Minimum Obligations Under Lease Commitments) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 298
2020	118
2021	97
2022	44
2023	35
Thereafter	15
Total	$ 607

(Loss) Earnings per Share (Basi

(Loss) Earnings per Share (Basic and Diluted) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net (loss) income	$ (12,232)	$ 573	$ 357	$ 236	$ 247	$ 225	$ (11,302)	$ 708
Denominator for basic (loss) income per common share:
Weighted average common shares outstanding (in shares)	13,137,000			12,977,000			13,112,000	12,953,000
Denominator for diluted (loss) earnings per share:
Dilutive effect of stock options and restricted stock (in shares)	0			277,000			0	275,000
Diluted weighted average shares (in shares)	13,137,000			13,254,000			13,112,000	13,228,000
(Loss) Earnings per common share:
Basic (in USD per share)	$ (0.93)			$ 0.02			$ (0.86)	$ 0.05
Diluted (in USD per share)	$ (0.93)			$ 0.02			$ (0.86)	$ 0.05
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares not included in the computation of dilutive income (loss) per share (in shares)	0			126,334			0	82,167
Antidilutive Effect
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Exercise price of shares not included in the computation of dilutive income (loss) per share, lower limit (in USD per share)				$ 22.90				$ 28.15
Exercise price of shares not included in the computation of dilutive income (loss) per share, upper limit (in USD per share)				$ 33.36				$ 33.36

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)segment	Sep. 30, 2018USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment			1
Revenue	$ 20,852	$ 16,396	$ 58,738	$ 49,318
Operating costs and corporate expenses	29,551	16,440	66,635	48,786
Inventory allowance	3,350		3,350	0
Retirement of rental equipment	1,512		1,512	0
Total other income, net	89	180	567	179
(Loss) Income before provision for income taxes	(13,472)	136	(12,192)	711
Corporate
Segment Reporting Information [Line Items]
Revenue	0	0	0	0
Operating costs and corporate expenses	18,697	7,889	35,113	23,055
Inventory allowance	0		0
Retirement of rental equipment	0		0
Total other income, net	89	180	567	179
(Loss) Income before provision for income taxes	(18,608)	(7,709)	(34,546)	(22,876)
Rental
Segment Reporting Information [Line Items]
Revenue	14,434	12,039	41,393	34,937
Operating costs and corporate expenses	6,300	5,363	18,544	15,262
Inventory allowance	987		987
Retirement of rental equipment	1,512		1,512
Total other income, net	0	0	0	0
(Loss) Income before provision for income taxes	5,635	6,676	20,350	19,675
Sales
Segment Reporting Information [Line Items]
Revenue	5,877	3,947	15,816	13,328
Operating costs and corporate expenses	4,390	3,081	12,508	10,196
Inventory allowance	2,363		2,363
Retirement of rental equipment	0		0
Total other income, net	0	0	0	0
(Loss) Income before provision for income taxes	(876)	866	945	3,132
Service and maintenance
Segment Reporting Information [Line Items]
Revenue	541	410	1,529	1,053
Operating costs and corporate expenses	164	107	470	273
Inventory allowance	0		0
Retirement of rental equipment	0		0
Total other income, net	0	0	0	0
(Loss) Income before provision for income taxes	$ 377	$ 303	$ 1,059	$ 780

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Aug. 12, 2019
Commitments and Contingencies Disclosure [Abstract]
Contractual obligation	$ 375,000,000	$ 375,000,000
Authorized repurchase amount			$ 10,000,000
Shares repurchased (in shares)		37,936
Value of shares repurchased	490,000	$ 490,000
Average price (in dollars per share)		$ 12.91
Remaining authorized repurchase amount	$ 9,500,000	$ 9,500,000

Related Party (Details)

Related Party (Details) - Corporate Joint Venture - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2016
Related Party Transaction [Line Items]
Purchases from joint venture	$ 1
N-G, LLC
Related Party Transaction [Line Items]
Percent ownership		50.00%
Genis Holdings, LLC | N-G, LLC
Related Party Transaction [Line Items]
Percent ownership		50.00%