XML 58 R47.htm IDEA: XBRL DOCUMENT v3.19.2

8. Stock-Based Compensation (Details 2) - SARs - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Risk-free interest rate	2.20%	2.60%
Expected volatility	101.00%	125.00%
Market value per share	$ .85	$ .61
Fair value per share on grant date	$ 1.14	$ 1.08

X

- References

No definition available.

+ Details

Name:	AMTX_FairValuePerShareOnGrantDate
Namespace Prefix:	AMTX_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	AMTX_MarketValuePerShare
Namespace Prefix:	AMTX_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iv)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_StockAppreciationRightsSARSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: