Investments and Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2016

Investments And Fair Value Of Financial Instruments [Abstract]

Summary of Amortized Cost and Fair Value of the Available-For-Sale Investment Securities Portfolio

The following tables summarize the amortized cost and fair value of the available-for-sale investment securities portfolio at June 30, 2016 and December 31, 2015, and the corresponding amounts of unrealized gains and losses recognized in accumulated other comprehensive income (“AOCI”):

(Dollars in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
June 30, 2016
Cash equivalents:
Money market funds	$	26,622	$	—	$	—		$	26,622
Short-term investments:
Certificates of Deposit		3,046		—		(4	)		3,042
U.S. government securities		22,824		5		(1	)		22,828
U.S. government agency securities		1,002		—		—			1,002
Long-term investments:
Certificates of Deposit		1,916		1		(3	)		1,914
U.S. government agency securities		5,000		—		(4	)		4,996
Totals	$	60,410	$	6	$	(12	)	$	60,404

(Dollars in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
December 31, 2015
Cash equivalents:
Money market funds	$	12,799	$	—	$	—		$	12,799
Commercial paper		5,949		—		—			5,949
U.S. government agency securities		3,049		—		—			3,049
Short-term investments:
Certificates of Deposit		3,374		—		—			3,374
Commercial paper		3,598		—		—			3,598
U.S. government securities		13,678		—		(30	)		13,648
U.S. government agency securities		5,653		1		(4	)		5,650
Long-term investments:
Certificates of Deposit		3,049		—		—			3,049
U.S. government securities		11,780		—		(52	)		11,728
U.S. government agency securities		5,001		—		(30	)		4,971
Totals	$	67,930	$	1	$	(116	)	$	67,815

Summary of Fair Value of Available-for-Sale Investments

The fair value of the available-for-sale investments at June 30, 2016 and December 31, 2015 were as follows:

	Fair Value Measurements at June 30, 2016
(Dollars in thousands)	Level 1		Level 2		Level 3		Total
Assets at Fair Value
Cash equivalents:
Money market funds	$	26,622	$	—	$	—	$	26,622
Short-term investments:
Certificates of Deposit		—		3,042		—		3,042
U.S. government securities		22,828		—		—		22,828
U.S. government agency securities		—		1,002		—		1,002
Long-term investments:
Certificates of Deposit		—		1,914		—		1,914
U.S. government agency securities		—		4,996		—		4,996
Total Assets at Fair Value	$	49,450	$	10,954	$	—	$	60,404

	Fair Value Measurements at December 31, 2015
(Dollars in thousands)	Level 1		Level 2		Level 3		Total
Assets at Fair Value
Cash equivalents:
Money market funds	$	12,799	$	—	$	—	$	12,799
Commercial paper		—		5,949		—		5,949
U.S. government agency securities		—		3,049		—		3,049
Short-term investments:
Certificates of Deposit		—		3,374		—		3,374
Commercial paper		—		3,598		—		3,598
U.S. government securities		13,648		—		—		13,648
U.S. government agency securities		—		5,650		—		5,650
Long-term investments:
Certificates of Deposit		—		3,049		—		3,049
U.S. government securities		11,728		—		—		11,728
U.S. government agency securities		—		4,971		—		4,971
Total Assets at Fair Value	$	38,175	$	29,640	$	—	$	67,815

Summary of Changes in Fair Value and Other Adjustments of Derivative Liabilities

The following table sets forth a summary of the changes in the fair value and other adjustments of these derivative liabilities (in thousands):

	Three Months Ended June 30,					Six Months Ended June 30,
	2016		2015			2016		2015
Beginning balance	$	—	$	2,979		$	—	$	1,580
Change in fair value and other adjustments		—		(291	)		—		1,108
Ending balance	$	—	$	2,688		$	—	$	2,688