Note 4 - Investments (Tables)

6 Months Ended

Jun. 30, 2017

Notes Tables

Unrealized Gain (Loss) on Investments [Table Text Block]

	Amortized cost		Unrealized gain		Unrealized loss		Estimated Fair Value
US government securities	$	1,796	$	—	$	—	$	1,796
Total marketable securities	$	1,796	$	—	$	—	$	1,796