Financial Instruments and Fair Value Measurements - Summary of Available-for-Sale Marketable Securities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2017	Dec. 31, 2016
Schedule Of Available For Sale Securities [Line Items]
Gross Unrealized Gains	$ 12	$ 30
Gross Unrealized Losses	(107)	(77)
Investments and cash equivalents, total	42,722	54,196
Investments and cash equivalents, fair value, total	$ 42,627	$ 54,149
U.S. treasuries
Schedule Of Available For Sale Securities [Line Items]
Contractual maturities (less than)	3 years	3 years
Certificates of deposit, at carrying value
Schedule Of Available For Sale Securities [Line Items]
Contractual maturities (less than)	1 year	1 year
Level I \| U.S. treasuries
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 39,900	$ 51,376
Gross Unrealized Gains	5	25
Gross Unrealized Losses	(107)	(77)
Estimated Fair Value	39,798	51,324
Level I \| Mutual funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	500	500
Gross Unrealized Gains	7	5
Gross Unrealized Losses	0	0
Estimated Fair Value	507	505
Level I \| U.S. Treasuries & Mutual Funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	40,400	51,876
Gross Unrealized Gains	12	30
Gross Unrealized Losses	(107)	(77)
Estimated Fair Value	40,305	51,829
Level II \| Certificates of deposit, at carrying value
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	2,322	2,320
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	$ 2,322	$ 2,320

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Sum of investments and unrestricted cash as of the balance sheet date.

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