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Term Loan Obligations (Details) - USD ($) $ / shares in Units, $ in Thousands						3 Months Ended		9 Months Ended
	Mar. 29, 2020	Mar. 28, 2020	Apr. 29, 2019	Apr. 25, 2019	May 29, 2015	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Warrant exercise price (in dollars per share)						$ 2.25		$ 2.25
Interest expense						$ 253	$ 366	$ 854	$ 1,477
Non-cash amortization						$ 100	$ 100	$ 400	$ 400
Loan and Security Agreement [Member] | Sale of the Japanese Subsidiary and Certain Assets [Member]
Debt Instrument [Line Items]
Payments for principal, interest and fees				$ 1,400
Term Loan [Member]
Debt Instrument [Line Items]
Origination Date					May 29, 2015
Original Loan Amount					$ 17,700
Basis variable rate					7.95%
Maturity date	Sep. 01, 2024	Sep. 01, 2021			Sep. 01, 2024
Fees amount associated with loan					$ 3,200
Number of shares callable by warrants (in shares)					188
Warrant exercise price (in dollars per share)					$ 5,175
Date from which warrants are exercisable					Nov. 30, 2015
Warrant expiration date					May 29, 2025
Minimum liquidity covenant										$ 2,000
Debt principal repayment start date	May 01, 2021		May 01, 2020
Prepayments of term loan	$ 5,000
Related final payment	300
Term loan, remaining amount	4,300
Amendment fee	$ 1,000
Debt instrument, covenant compliance								the Company was in compliance with all of the debt covenants under the Loan and Security Agreement.
Term Loan [Member] | Loan and Security Agreement [Member] | Sale of the Japanese Subsidiary and Certain Assets [Member]
Debt Instrument [Line Items]
Payments for principal, interest and fees				$ 3,100
Term Loan [Member] | LIBOR [Member] | Interest Rate Floor [Member]
Debt Instrument [Line Items]
Basis variable rate					1.00%
Term Loan [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate					8.95%
Term Loan [Member] | Maximum [Member]
Debt Instrument [Line Items]
Amount of loan outstanding threshold in order to release intellectual property asset collateral								$ 4,300

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