Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Assets:
Securities	$ 86,276
Other assets	25,252	$ 6,294
Fair Value Measurements, Recurring Basis
Assets:
Cash and cash equivalents	78,300	146,200
Total assets measured at fair value	176,127	160,849
Other assets		1,900
Fair Value Measurements, Recurring Basis \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total assets measured at fair value	78,868	46,257
Fair Value Measurements, Recurring Basis \| Significant Other Observable Inputs (Level 2)
Assets:
Total assets measured at fair value	97,259	112,702
Fair Value Measurements, Recurring Basis \| Significant Unobservable Inputs (Level 3)
Assets:
Total assets measured at fair value	0	1,890
Fair Value Measurements, Recurring Basis \| Money market funds
Assets:
Cash and cash equivalents	67,321	46,257
Fair Value Measurements, Recurring Basis \| Money market funds \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and cash equivalents	67,321	46,257
Fair Value Measurements, Recurring Basis \| Money market funds \| Significant Other Observable Inputs (Level 2)
Assets:
Cash and cash equivalents	0	0
Fair Value Measurements, Recurring Basis \| Money market funds \| Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents	0	0
Fair Value Measurements, Recurring Basis \| U.S. Treasury securities
Assets:
Securities		12,488
Fair Value Measurements, Recurring Basis \| U.S. Treasury securities \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Securities		0
Fair Value Measurements, Recurring Basis \| U.S. Treasury securities \| Significant Other Observable Inputs (Level 2)
Assets:
Securities		12,488
Fair Value Measurements, Recurring Basis \| U.S. Treasury securities \| Significant Unobservable Inputs (Level 3)
Assets:
Securities		0
Fair Value Measurements, Recurring Basis \| Government-sponsored enterprises
Assets:
Securities	11,695
Fair Value Measurements, Recurring Basis \| Government-sponsored enterprises \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Securities	0
Fair Value Measurements, Recurring Basis \| Government-sponsored enterprises \| Significant Other Observable Inputs (Level 2)
Assets:
Securities	11,695
Fair Value Measurements, Recurring Basis \| Government-sponsored enterprises \| Significant Unobservable Inputs (Level 3)
Assets:
Securities	0
Fair Value Measurements, Recurring Basis \| Corporate debt securities
Assets:
Securities	85,564	100,214
Fair Value Measurements, Recurring Basis \| Corporate debt securities \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Securities	0	0
Fair Value Measurements, Recurring Basis \| Corporate debt securities \| Significant Other Observable Inputs (Level 2)
Assets:
Securities	85,564	100,214
Fair Value Measurements, Recurring Basis \| Corporate debt securities \| Significant Unobservable Inputs (Level 3)
Assets:
Securities	0	0
Fair Value Measurements, Recurring Basis \| Corporate equity securities
Assets:
Securities	11,547
Fair Value Measurements, Recurring Basis \| Corporate equity securities \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Securities	11,547
Fair Value Measurements, Recurring Basis \| Corporate equity securities \| Significant Other Observable Inputs (Level 2)
Assets:
Securities	0
Fair Value Measurements, Recurring Basis \| Corporate equity securities \| Significant Unobservable Inputs (Level 3)
Assets:
Securities	$ 0
Fair Value Measurements, Recurring Basis \| Warrant
Assets:
Securities		1,890
Fair Value Measurements, Recurring Basis \| Warrant \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Securities		0
Fair Value Measurements, Recurring Basis \| Warrant \| Significant Other Observable Inputs (Level 2)
Assets:
Securities		0
Fair Value Measurements, Recurring Basis \| Warrant \| Significant Unobservable Inputs (Level 3)
Assets:
Securities		$ 1,890

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Publisher FASB
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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of noncurrent assets classified as other.

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