Risks and Uncertainties	6 Months Ended
Mar. 31, 2021
Risks And Uncertainties [Abstract]
Risks and Uncertainties	15. Risks and Uncertainties Concentration of Credit Risk As of March 31, 2021, the Company had combined trade accounts and notes receivable and unbilled receivables from three customers of $6.9 million, $4.2 million and $1.0 million. During the six months ended March 31, 2021, revenue recognized from these three customers was $13.2 million, $12.7 million and $8.9 million, respectively. COVID-19 Pandemic The ongoing COVID-19 pandemic has spread across the globe and has negatively impacted worldwide economic activity, including the global demand for oil and natural gas, and continues to create challenges in the Company’s markets. In addition to measures the Company has taken voluntarily, the government authorities in the Company’s markets have taken actions to mitigate the spread of COVID-19, including travel restrictions, border closings, restrictions on public gatherings, stay-at-home orders and other quarantine and isolation measures. Following the initial outbreak of the virus, the Company experienced disruptions in its supply chain, a reduction in demand for certain products, cancellation of rental contracts and difficulty with field employees and salespeople traveling domestically and abroad to conduct the Company’s business. COVID-19 continues to pose the risk that the Company or its employees, contractors, suppliers and customers may be prevented from conducting business activities for an indefinite period of time, including potential spread of the disease within these groups or restrictions that may be requested or mandated by governmental authorities, including quarantines of certain geographic areas, restrictions on travel and other restrictions that prohibit employees from going to work, both around the world as well as in certain jurisdictions in the United States. The continued spread of COVID–19 and the related mitigation measures have disrupted the Company’s supply chain, resulting in longer lead times in materials shipped from suppliers and extended the shipping time for these materials to reach the Company’s facilities. If COVID–19 continues to spread or the response to contain the COVID–19 pandemic is unsuccessful, the Company could experience a material adverse effect on its business, financial condition, results of operations and liquidity. Decrease in Oil Commodity Price Levels Demand for many of the Company’s products and the profitability of its operations depend primarily on the level of worldwide oil and gas exploration activity. Prevailing oil and gas prices, with an emphasis on crude oil prices, and market expectations regarding potential changes in such prices significantly affect the level of worldwide oil and gas exploration activity. During periods of improved energy commodity prices, the capital spending budgets of oil and natural gas operators tend to expand, which results in increased demand for the Company’s products. Conversely, in periods when these energy commodity prices deteriorate, capital spending budgets of oil and natural gas operators tend to contract and the demand for the Company’s products generally weakens. Historically, the markets for oil and gas have been volatile and are subject to wide fluctuations in response to changes in the supply of and demand for oil and gas, market uncertainty and a variety of additional factors that are beyond its control. These factors include the level of consumer demand, regional and international economic conditions, weather conditions, domestic and foreign governmental regulations (including those related to climate change), price and availability of alternative fuels, political conditions, instability and hostilities in the Middle East and other significant oil-producing regions, increases and decreases in the supply of oil and gas, the effect of worldwide energy conservation measures and the ability of OPEC to set and maintain production levels and prices of foreign imports. Sustained low oil prices or the failure of oil prices to rise in the future and the resulting downturns or lack of growth in the energy industry and energy‑related business, could have a negative impact on the Company’s results of operations and financial condition. In light of the decline in oil prices caused by the COVID-19 pandemic in 2020, oil and gas exploration and production companies experienced a significant reduction in cash flows, which resulted in reductions in their capital spending budgets for oil and gas exploration-focused activities, including seismic data acquisition activities. Demand for the sale of the Company’s seismic products targeted at customers in its Oil and Gas Markets segment, which has historically accounted for the majority of its revenue, significantly declined during fiscal year 2020, and both product sales and rental revenue could significantly diminish during the remainder of fiscal year 2021 or beyond as a result of significant uncertainty in the outlook for oil and gas exploration. Specifically, the Company expects these challenging industry conditions to result in decreased demand for its marine wireless nodal products and its land-based seismic products, as the demand for such products has been, and will likely continue to be, vulnerable to downturns in the economy and the oil and gas industry in general. In addition to the negative effects of slowdowns in the United States economy, slowing economic growth in growing economies like those in China and India could lead to a decline in demand for crude oil and natural gas. Slowdowns in economic activity would likely reduce worldwide demand for energy and result in an extended period of lower crude oil and natural gas prices. Any material changes in oil and gas prices or other market trends that adversely impact seismic exploration activity would likely affect the demand for the Company’s products and could materially and adversely affect its results of operations and liquidity. Generally, imbalances in the supply and demand for oil and gas will affect oil and gas prices and, in such circumstances, demand for the Company’s oil and gas products may be adversely affected when world supplies exceed demand.

Risks and Uncertainties

6 Months Ended

Mar. 31, 2021

15. Risks and Uncertainties

Concentration of Credit Risk

As of March 31, 2021, the Company had combined trade accounts and notes receivable and unbilled receivables from three customers of $6.9 million, $4.2 million and $1.0 million. During the six months ended March 31, 2021, revenue recognized from these three customers was $13.2 million, $12.7 million and $8.9 million, respectively.

COVID-19 Pandemic

The ongoing COVID-19 pandemic has spread across the globe and has negatively impacted worldwide economic activity, including the global demand for oil and natural gas, and continues to create challenges in the Company’s markets. In addition to measures the Company has taken voluntarily, the government authorities in the Company’s markets have taken actions to mitigate the spread of COVID-19, including travel restrictions, border closings, restrictions on public gatherings, stay-at-home orders and other quarantine and isolation measures. Following the initial outbreak of the virus, the Company experienced disruptions in its supply chain, a reduction in demand for certain products, cancellation of rental contracts and difficulty with field employees and salespeople traveling domestically and abroad to conduct the Company’s business. COVID-19 continues to pose the risk that the Company or its employees, contractors, suppliers and customers may be prevented from conducting business activities for an indefinite period of time, including potential spread of the disease within these groups or restrictions that may be requested or mandated by governmental authorities, including quarantines of certain geographic areas, restrictions on travel and other restrictions that prohibit employees from going to work, both around the world as well as in certain jurisdictions in the United States. The continued spread of COVID–19 and the related mitigation measures have disrupted the Company’s supply chain, resulting in longer lead times in materials shipped from suppliers and extended the shipping time for these materials to reach the Company’s facilities. If COVID–19 continues to spread or the response to contain the COVID–19 pandemic is unsuccessful, the Company could experience a material adverse effect on its business, financial condition, results of operations and liquidity.

Decrease in Oil Commodity Price Levels

Demand for many of the Company’s products and the profitability of its operations depend primarily on the level of worldwide oil and gas exploration activity. Prevailing oil and gas prices, with an emphasis on crude oil prices, and market expectations regarding potential changes in such prices significantly affect the level of worldwide oil and gas exploration activity. During periods of improved energy commodity prices, the capital spending budgets of oil and natural gas operators tend to expand, which results in increased demand for the Company’s products. Conversely, in periods when these energy commodity prices deteriorate, capital spending budgets of oil and natural gas operators tend to contract and the demand for the Company’s products generally weakens. Historically, the markets for oil and gas have been volatile and are subject to wide fluctuations in response to changes in the supply of and demand for oil and gas, market uncertainty and a variety of additional factors that are beyond its control. These factors include the level of consumer demand, regional and international economic conditions, weather conditions, domestic and foreign governmental regulations (including those related to climate change), price and availability of alternative fuels, political conditions, instability and hostilities in the Middle East and other significant oil-producing regions, increases and decreases in the supply of oil and gas, the effect of worldwide energy conservation measures and the ability of OPEC to set and maintain production levels and prices of foreign imports.

Sustained low oil prices or the failure of oil prices to rise in the future and the resulting downturns or lack of growth in the energy industry and energy‑related business, could have a negative impact on the Company’s results of operations and financial condition. In light of the decline in oil prices caused by the COVID-19 pandemic in 2020, oil and gas exploration and production companies experienced a significant reduction in cash flows, which resulted in reductions in their capital spending budgets for oil and gas exploration-focused activities, including seismic data acquisition activities. Demand for the sale of the Company’s seismic products targeted at customers in its Oil and Gas Markets segment, which has historically accounted for the majority of its revenue, significantly declined during fiscal year 2020, and both product sales and rental revenue could significantly diminish during the remainder of fiscal year 2021 or beyond as a result of significant uncertainty in the outlook for oil and gas exploration. Specifically, the Company expects these challenging industry conditions to result in decreased demand for its marine wireless nodal products and its land-based seismic products, as the demand for such products has been, and will likely continue to be, vulnerable to downturns in the economy and the oil and gas industry in general. In addition to the negative effects of slowdowns in the United States economy, slowing economic growth in growing economies like those in China and India could lead to a decline in demand for crude oil and natural gas. Slowdowns in economic activity would likely reduce worldwide demand for energy and result in an extended period of lower crude oil and natural gas prices. Any material changes in oil and gas prices or other market trends that adversely impact seismic exploration activity would likely affect the demand for the Company’s products and could materially and adversely affect its results of operations and liquidity.

Generally, imbalances in the supply and demand for oil and gas will affect oil and gas prices and, in such circumstances, demand for the Company’s oil and gas products may be adversely affected when world supplies exceed demand.