CASH, CASH EQUIVALENTS AND INVESTMENTS

The Company considers all highly liquid debt instruments purchased with an original maturity of three months or less to be cash equivalents. The Company classifies its remaining investments as available-for-sale. These securities are carried at fair market value, with unrealized gains and losses reported in shareholders’ equity. Gains or losses on securities sold are based on the specific identification method.

Investments at June 30, 2013 consisted of the following (in thousands):



	Amortized		Unrealized					Aggregate Fair
Investment Classification	Cost		Gains		(Losses)			Market Value
June 30, 2013 –
Certificates of deposit	$	9,117	$	3	$	(12	)	$	9,108
Commercial paper	2,000		—		—			2,000
Corporate bonds	151,255		38		(9		)	151,284
U.S. government bonds	3,074		—		(2		)	3,072
Convertible notes	4,300		—		—			4,300
	$	169,746	$	41	$	(23	)	$	169,764

Investments at December 31, 2012 consisted of the following (in thousands):



	Amortized		Unrealized					Aggregate Fair
Investment Classification	Cost		Gains		(Losses)			Market Value
December 31, 2012 –
Certificates of deposit	$	7,562	$	3	$	(5	)	$	7,560
Commercial paper	2,997		—		—			2,997
Corporate bonds	141,349		9		(25		)	141,333
U.S. government bonds	3,098		—		—			3,098
Convertible notes	4,300		—		—			4,300
	$	159,306	$	12	$	(30	)	$	159,288

On July 13, 2012, the Company entered into a three-year joint development agreement with Plextronics, Inc. (Plextronics), a private company engaged in printed solar, lighting and other electronics-related research and development. Under the joint development agreement, the Company is committed to pay $1.0 million per year to Plextronics for three years. In addition, the Company invested $4.0 million in Plextronics through the purchase of a convertible promissory note. The Company also received warrants to purchase shares of preferred stock in connection with the purchase of the convertible note. The note accrues interest at the rate of 3% per year. The Company modified the note extending its due date beyond the original due date of June 30, 2013. Depending on certain conditions, the note may either convert automatically, or if other certain conditions are met, the Company has the option to convert the note into shares of Plextronics’ preferred stock at a specified conversion price. The note was classified as a long-term investment at June 30, 2013, and was classified as a short-term investment at December 31, 2012.

On July 17, 2012, the Company invested $300,000 in a private company engaged in plasma processing equipment research and development (the Borrower) through the purchase of a convertible promissory note. The note accrues interest at the rate of 5% per year and is due and payable by August 1, 2015. The note is included in long-term investments on the consolidated balance sheet. The Company has the option to convert the note into shares of the Borrower’s preferred stock at a specified conversion price.

All short-term investments held at June 30, 2013 will mature within one year.