Note 4 - Revenue Recognition (Details) - Analysis of the Chargeback Liability (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2014	Dec. 31, 2013
Analysis of the Chargeback Liability [Abstract]
Beginning balance	$ 18,104	$ 11,898
Ending balance	12,298	18,104
Provision related to sales made in the current period	118,643	213,075
Credits issued to third parties	$ (124,449)	$ (206,869)

Represents the amount the Company agrees to reimburse wholesalers for differences between the gross sales prices, at which the Company sells its products to wholesalers and the actual prices of such products at the time wholesalers resell them under the Company’s various contractual arrangements with third parties such as hospitals and group purchasing organizations.

No definition available.

Name:	amph_RevenueRecognitionWholesalerChargebacks
Namespace Prefix:	amph_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant