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v3.3.1.900

Selected Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Revenues-oil and natural gas sales | $ 17,523 | [1] | $ 17,546 | [1] | $ 27,137 | [1] | $ 18,239 | [1] | $ 23,037 | [1] | $ 24,486 | [1] | $ 52,098 | [1] | $ 28,071 | [1] | $ 80,445 | $ 127,691 | $ 169,277
Total operating costs and expenses | 89,301 | [2] | 49,667 | [2] | 28,225 | [2] | 53,857 | [2] | 117,308 | [2] | 17,799 |  | 18,270 |  | 28,721 |  | 221,050 | 182,097 | 92,052
Operating income (loss) | (75,124) |  | (32,121) |  | (1,030) |  | (35,278) |  | (94,270) |  | 6,687 |  | 33,828 |  | (650) |  | (143,553) | (54,406) | 77,225
Net income (loss) | $ (80,779) |  | $ (33,668) |  | $ (5,204) |  | $ (39,005) |  | $ (98,332) |  | $ 3,109 |  | $ 24,711 |  | $ (7,038) |  | $ (158,656) | $ (77,550) | $ 43,072
Basic net income (loss) per share | $ (1.38) |  | $ (0.58) |  | $ (0.09) |  | $ (0.67) |  | $ (1.70) |  | $ 0.05 |  | $ 0.43 |  | $ (0.12) |  | $ (2.72) | $ (1.36) | $ 0.75
Diluted net income (loss) per share | $ (1.38) |  | $ (0.58) |  | $ (0.09) |  | $ (0.67) |  | $ (1.70) |  | $ 0.05 |  | $ 0.43 |  | $ (0.12) |  | $ (2.72) | $ (1.36) | $ 0.74
Impairment of proved properties | $ 52,100 |  | $ 18,000 |  | $ 5,800 |  | $ 5,400 |  | $ 98,300 |  |  |  |  |  |  |  | $ 81,322 | $ 98,341 |
Impairments of undeveloped leasehold costs | 8,800 |  | 0 |  | $ 600 |  | 2,700 |  | 2,300 |  | $ 0 |  | $ 800 |  | $ 800 |  |  |  |
Dry hole costs |  |  | 9,000 |  |  |  | $ 24,500 |  |  |  |  |  | $ 2,000 |  | $ 9,700 |  | 45,652 | 13,273 | $ 22,490
Bad debt expense |  |  | 2,700 |  |  |  |  |  | $ 600 |  | $ 1,800 |  |  |  |  |  | 2,968 | 2,400 | 3,326
Inventory write-off | 3,400 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Scenario, Adjustment [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating income (loss) |  |  | 3,600 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Impairments of undeveloped leasehold costs |  |  | $ 3,600 |  |  |  |  |  |  |  |  |  |  |  |  |  | 7,000 |  |
Scenario, Adjustment [Member] | Gabon [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues-oil and natural gas sales | (2,300) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Misstatement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating income (loss) | $ (2,300) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
VAALCO ENERGY, INC. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total operating costs and expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10,162 | 6,834 | 5,813
Operating income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (10,162) | (6,834) | (5,813)
Net income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ (158,656) | $ (77,550) | $ 43,072
[1] | As discussed in Note 3 to the consolidated financial statements an error was identified the prepaid royalty account that caused previous periods to be misstated. Total revenues were corrected through an out of period adjustment in the fourth quarter of 2015 with reduction of $2.3 million, overstating operating loss and net loss by $2.3 million.
[2] | Significant cost and expense items that caused total operating costs and expenses to vary among the quarters are impairments of proved properties and undeveloped leasehold costs, dry hole costs, bad debt expense and inventory write-offs.

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