Marketable Securities

12 Months Ended

Dec. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Note 5 - Marketable Securities

The Company's investment in marketable securities as of December 31, 2016 and 2017 are classified as ''held-to-maturity'' and consist of the following:

			Gross		Gross
			unrealized		unrealized
	Amortized		holding		holding			Aggregate
	cost basis**		gains		(losses)			fair value*
	US$ thousands
At December 31, 2017
Held to maturity:
Corporate debt securities
Current		7,798		-		(49	)		7,749
Non-Current		5,976		-		(95	)		5,881

		13,774		-		(144	)		13,630

At December 31, 2016
Held to maturity:
Corporate debt securities
Current		16,390		-		(97	)		16,293
Non-Current		7,815		-		(62	)		7,753

		24,205		-		(159	)		24,046

*	Fair value is being determined using quoted market prices in active markets (Level 1).
**	Including accrued interest in the amount of US$ 173 thousand and US$ 77 thousand as of December 31, 2016 and 2017 respectively. The accrued interest is presented as part of other account receivable on the balance sheet.

Activity in marketable securities in 2017	US$ thousands

Balance at January 1, 2017		24,205

Purchases of marketable securities		5,961
Discount on marketable securities, net		(217	)
Proceeds from maturity of marketable securities		(16,175	)
Balance at December 31, 2017		13,774

The following table summarizes the gross unrealized losses on investment securities for which other-than-temporary impairments have not been recognized and the fair value of those securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2017:

	Less than 12 months					12 months or more					Total
	Unrealized Losses			Fair value		Unrealized Losses			Fair value		Unrealized Losses			Fair value
Held to maturity:

Corporate debt securities		(95	)		5,881		(49	)		7,749		(144	)		13,630

The unrealized losses on the investments were caused by changes in interest rate. The Company has the ability and intent to hold these investments until maturity and it is more likely than not that the Company will not be required to sell any of the securities before recovery; therefore these investments are not considered other than temporarily impaired.