Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)		3 Months Ended	6 Months Ended	12 Months Ended
	Jul. 01, 2019	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Jan. 01, 2019
Significant Accounting Policies [Line Items]
Restricted cash		$ 113,680,000	$ 113,680,000
Short-term capitalized contract costs included in prepaid assets and other current assets		137,000	137,000		$ 209,000
Long-term capitalized contract costs included in included in other assets		79,000	79,000		128,000
Amortization of capitalized contract costs recorded to selling, general and administrative expenses		55,000	121,000
Contract assets included in prepaid expenses and other current assets		534,000	534,000		28,000
Revenue remaining performance obligation amount		34,245,000	34,245,000
Assets		435,651,000	435,651,000	$ 474,649,000
Liabilities		366,038,000	366,038,000	399,793,000
Accumulated deficit		(92,906,000)	(92,906,000)	(81,008,000)
Accrued expenses and other current liabilities		23,099,000	23,099,000	36,992,000
Inventory		74,066,000	74,066,000	50,997,000
Accounts receivable, net		52,852,000	52,852,000	84,170,000
Deferred tax assets		26,367,000	26,367,000	21,578,000
Accounting Standards Update 2014-09
Significant Accounting Policies [Line Items]
Assets					473,798,000
Liabilities					396,792,000
Accumulated deficit					(78,858,000)
Accrued expenses and other current liabilities					38,037,000
Inventory					50,629,000
Deferred tax assets					20,986,000
Accounting Standards Update 2014-09 | Adjustments
Significant Accounting Policies [Line Items]
Assets		917,000	917,000		(851,000)
Liabilities		3,547,000	3,547,000		(3,001,000)
Accumulated deficit		(2,630,000)	(2,630,000)		2,150,000
Deferred revenue, net					(4,046,000)
Accrued expenses and other current liabilities		(683,000)	(683,000)		1,045,000
Inventory		248,000	248,000		(368,000)
Prepaid expenses and other current assets and other assets					337,000
Accounts receivable, net					(228,000)
Deferred tax assets		402,000	402,000		$ (592,000)
Deferred revenue
Significant Accounting Policies [Line Items]
Revenue		5,919,000	13,188,000
Interest Income
Significant Accounting Policies [Line Items]
Other revenue		50,000	$ 76,000
Software
Significant Accounting Policies [Line Items]
Warranty period			90 days
Hardware
Significant Accounting Policies [Line Items]
Warranty period			1 year
Accounts Receivable, Extended Payment Terms
Significant Accounting Policies [Line Items]
Reserve for credit losses		0	$ 0	0
Write off of uncollectible receivables			$ 0	0
Minimum
Significant Accounting Policies [Line Items]
Extended payment period for certain customers and/or for certain transactions			1 year
Maintenance and support services and professional services revenue, recognition period			3 years
Maximum
Significant Accounting Policies [Line Items]
Extended payment period for certain customers and/or for certain transactions			5 years
Maintenance and support services and professional services revenue, recognition period			5 years
NetComm
Significant Accounting Policies [Line Items]
Restricted cash		112,674,000	$ 112,674,000
NetComm | Subsequent Event
Significant Accounting Policies [Line Items]
Business acquisition, closing date	Jul. 01, 2019
Certificates of Deposit
Significant Accounting Policies [Line Items]
Restricted cash		$ 1,006,000	$ 1,006,000	$ 1,019,000