Note 13 - Stock Based Compensation - Summary of Nonvested Stock Options, Restricted Stock and Performance Shares (Details) - $ / shares	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2019
Employee Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Nonvested Stock Options, beginning balance	653,613	601,513
Granted, nonvested stock options	65,663	65,000
Vested during period, nonvested stock options	(1,250)	(7,000)
Forfeited, nonvested stock options	(2,067)	(5,900)
Nonvested Stock Options, ending balance	715,959	653,613
Nonvested Stock Options, beginning balance, weighted average grant date fair value	$ 17.65	$ 17.83
Granted, weighted average grant date fair value	16.40	15.04
Vested during period, weighted average grant date fair value	16.32	9.26
Forfeited, weighted average grant date fair value	17.50	17.36
Nonvested Stock Options, ending balance, weighted average grant date fair value	$ 17.54	$ 17.65
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Nonvested equity awards other than options, beginning balance	25,000
Granted, weighted average grant date fair value	15,729	25,000
Nonvested equity awards other than options, ending balance	40,729	25,000
Nonvested equity awards other than options, beginning balance, weighted average grant date fair value	$ 44.21
Granted, equity awards other than options, weighted average grant date fair value	40.06	$ 44.21
Nonvested equity awards other than options, ending balance, weighted average grant date fair value	$ 42.61	$ 44.21
Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Nonvested equity awards other than options, beginning balance	151,250	152,000
Granted, weighted average grant date fair value		5,000
Forfeited, equity awards other than options	(17,250)	(5,750)
Nonvested equity awards other than options, ending balance	134,000	151,250
Nonvested equity awards other than options, beginning balance, weighted average grant date fair value	$ 46.80	$ 46.61
Granted, equity awards other than options, weighted average grant date fair value		45.64
Forfeited, equity awards other than options, weighted average grant date fair value	40.65	40.65
Nonvested equity awards other than options, ending balance, weighted average grant date fair value	$ 47.59	$ 46.80

CAMBREX CORP 10-Q