CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 2,369	$ 1,466
Accounts receivable, net	31,434	18,989
Unbilled receivables	8,081	7,823
Inventories	13,571	18,575
Prepaid expenses and other current assets	2,170	3,243
Total current assets	57,625	50,096
Property, plant and equipment, net	249,133	248,396
Operating right-of-use assets	34,329	0
Intangible assets, net	17,640	18,068
Other assets	3,613	3,732
Total assets	362,340	320,292
Current liabilities:
Accounts payable	8,488	11,336
Accrued and other expenses	11,003	8,392
Deferred revenue	5,005	4,095
Current portion of long-term debt	1,332	829
Current portion of operating lease liabilities	13,354	0
Total current liabilities	39,182	24,652
Long-term debt, net of current portion	51,296	47,893
Long-term operating lease liabilities, net of current portion	21,539	0
Long-term deferred tax liabilities, net	18,216	17,898
Asset retirement obligation	12,253	13,322
Contingent consideration	5,500	7,167
Total liabilities	147,986	110,932
Commitments and contingencies (Note 16)
Stockholders’ equity
Common stock, $0.001 par value, 350,000,000 shares authorized; 40,725,196 issued and 40,020,447 outstanding at March 31, 2019; 40,673,513 issued and 39,974,478 outstanding at December 31, 2018	40	40
Treasury stock, at cost, 704,749 and 699,035 shares at March 31, 2019 and December 31, 2018, respectively	(2,862)	(2,839)
Additional paid-in capital	163,034	162,195
Retained earnings	54,310	50,277
Accumulated other comprehensive loss	(168)	(313)
Total stockholders’ equity	214,354	209,360
Total liabilities and stockholders’ equity	$ 362,340	$ 320,292

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.