Balance Sheet Account Details (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Restricted Cash and Cash Equivalents Items [Line Items]
Inventory reserves	$ 0.8	$ 0.8
4550 Towne Centre Court, San Diego, California \| Financial Standby Letter of Credit \| Letter of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Cash collateral as security	$ 0.9

Amount of valuation reserve for inventory.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant