Marketable Investments (Tables)

9 Months Ended

Sep. 30, 2016

Investments Debt And Equity Securities [Abstract]

Summary of Company's Marketable Investments

The following table summarizes the Company’s marketable investments (in thousands):

	As of  September 30, 2016
			Gross		Gross
	Amortized		Unrealized		Unrealized			Market
	Cost		Gains		Losses			Value
Federal agency obligations	$	1,801	$	—	$	(1	)	$	1,800
Corporate obligations		61,350		20		(66	)		61,304
Total	$	63,151	$	20	$	(67	)	$	63,104

	As of December 31, 2015
			Gross		Gross
	Amortized		Unrealized		Unrealized			Market
	Cost		Gains		Losses			Value
Corporate obligations	$	47,939	$	—	$	(164	)	$	47,775

Summary of Maturity Periods of Marketable Securities

The following table summarizes the maturity periods of the marketable securities in the Company’s portfolio as of September 30, 2016 (in thousands).

	FY 2016		FY 2017		FY 2018		Total
Federal agency obligations	$	—	$	—	$	1,800	$	1,800
Corporate obligations		3,000		37,220		21,084		61,304
Total	$	3,000	$	37,220	$	22,884	$	63,104

Summary of Gross Unrealized Losses and Market Value of Available-for-Sale Securities with Unrealized Losses

The following table shows the gross unrealized losses and market value of Forrester’s available-for-sale securities with unrealized losses that are not deemed to be other-than-temporary, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position (in thousands):

	As of  September 30, 2016
	Less Than 12 Months				12 Months or Greater
	Market		Unrealized		Market		Unrealized
	Value		Losses		Value		Losses
Federal agency obligations	$	1,800	$	1	$	—	$	—
Corporate obligations		45,562		66		—		—
Total	$	47,362	$	67	$	—	$	—

	As of December 31, 2015
	Less Than 12 Months				12 Months or Greater
	Market		Unrealized		Market		Unrealized
	Value		Losses		Value		Losses
Corporate obligations	$	45,748	$	158	$	2,027	$	6

Summary of Company's Fair Value Hierarchy for its Financial Assets

The following table represents the Company’s fair value hierarchy for its financial assets (cash equivalents and investments) measured at fair value on a recurring basis (in thousands):

	As of  September 30, 2016
	Level 1		Level 2		Level 3		Total
Money market funds (1)	$	528	$	—	$	—	$	528
Federal agency obligations		—		1,800		—		1,800
Corporate obligations		—		61,304		—		61,304
Total	$	528	$	63,104	$	—	$	63,632

	As of December 31, 2015
	Level 1		Level 2		Level 3		Total
Money market funds (1)	$	325	$	—	$	—	$	325
Corporate obligations		—		47,775		—		47,775
Total	$	325	$	47,775	$	—	$	48,100

(1) Included in cash and cash equivalents.