Commitments and Contingencies (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	May 31, 2017	Jun. 30, 2018 USD ($) ft²	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) ft²	Jun. 30, 2017 USD ($)
Product Warranty [Abstract]
Period of warranty				12 months
Change in warranty accrual [Roll Forward]
Beginning accrued product warranty		$ 117	$ 133	$ 133	$ 251
Accruals for warranties issued		74	37	133	70
Adjustments related to pre-existing warranties including expirations and changes in estimates		23	(27)	(23)	(132)
Cost of warranty repair		(36)	(13)	(65)	(59)
Ending accrued product warranty		$ 178	$ 130	$ 178	$ 130
Leases [Abstract]
Area of property under long-term operating lease (in square feet) | ft²		19,467		19,467
Additional years per lease option				3 years
Number of additional years to lease term	3 years
Term of royalty agreement				8 years
Aggregate amount payable towards royalty		$ 7,000		$ 7,000
Operating leases
Less than 1 year		217		217
1-3 years		252		252
4-5 years		24		24
Total		493		493
Royalty agreement
Less than 1 year		288		288
Total		288		288
Total
Less than 1 year		505		505
1-3 years		252		252
4-5 years		24		24
Total		781		781
Dingxing
Leases [Abstract]
Total investment agreement value		90,000		90,000
Kazuo
Leases [Abstract]
Total investment agreement value		15,000		15,000
Beijing BoYu Semiconductor Vessel Craftwork Technology Co., Ltd Investment | Kazuo
Leases [Abstract]
Total investment agreement value		$ 8,000		$ 8,000