Provision for Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Valuation allowance increased value	$ 19,700,000	$ 12,200,000
Net operating loss carryforwards	137,100,000
Interest or penalties accrued	0	0
Liability related to uncertain tax positions	0
Reserve for unrecognized tax benefits	2,165,000	$ 1,084,000	$ 622,000
Federal
Income Taxes [Line Items]
Net operating loss carryforwards	$ 47,400,000
Net operating loss carryforwards, expiration year	2035
Net operating loss carryforwards amount with no expiration date	$ 89,700,000
Federal | Earliest Tax Year | U.S.
Income Taxes [Line Items]
Open tax year	2015
Federal | Latest Tax Year | U.S.
Income Taxes [Line Items]
Open tax year	2018
Federal | Research
Income Taxes [Line Items]
Research tax credits	$ 6,100,000
Research tax credits, expiration year	2035
State
Income Taxes [Line Items]
Net operating loss carryforwards	$ 16,900,000
Net operating loss carryforwards, expiration year	2035
State | Earliest Tax Year | California
Income Taxes [Line Items]
Open tax year	2015
State | Latest Tax Year | California
Income Taxes [Line Items]
Open tax year	2018
State | Research
Income Taxes [Line Items]
Research tax credits	$ 5,000,000
Foreign Tax Authority | Earliest Tax Year | Australian Taxation Office
Income Taxes [Line Items]
Open tax year	2017
Foreign Tax Authority | Latest Tax Year | Australian Taxation Office
Income Taxes [Line Items]
Open tax year	2018