Revenue from Contracts with Customers (ASC 606) - Financial Statement Impact of Adopting ASC 606 (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash, cash equivalent and marketable securities	$ 18,075	$ 42,915
Accounts receivable, net	29,663	28,316	$ 28,316
Inventories	22,942	22,732	22,732
Contract assets	3,566	3,205	0
Prepaid expenses and other current assets	3,494	3,816	3,816
Long-lived assets	95,979	92,513
Other non-current assets	6,736	5,927	5,927
Contract assets, long-term	6,971	5,963	0
Non-current deferred income tax asset	226	222	20
Total assets	187,652	205,609	196,239
Accounts payable, accrued expenses, and other current liabilities	46,817	36,430
Deferred revenue, current	0	0	6,919
Contract liabilities	9,193	11,039	0
Long-term contract liabilities	9,070	7,998	0
Other long-term liabilities	3,620	2,653
Long-term debt, excluding current portion	19,437	44,572	44,572
Total liabilities	88,137	102,692	90,574
Accumulated deficit	(15,397)	(7,165)	(4,417)
Common stock, additional paid-in capital, and accumulated other comprehensive loss	114,912	110,082
Total stockholders’ equity	99,515	102,917	105,665	$ 106,502	$ 118,176
Total liabilities and stockholders’ equity	187,652	205,609	196,239
As Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash, cash equivalent and marketable securities	18,075		42,915
Accounts receivable, net	29,663		28,316
Inventories	22,942		22,732
Contract assets	0		0
Prepaid expenses and other current assets	3,494		3,816
Long-lived assets	95,979		92,513
Other non-current assets	6,736		5,927
Contract assets, long-term	0		0
Non-current deferred income tax asset	86		20
Total assets	176,975		196,239
Accounts payable, accrued expenses, and other current liabilities	46,817		36,430
Deferred revenue, current	4,833		6,919
Contract liabilities	0		0
Long-term contract liabilities	0		0
Other long-term liabilities	3,620		2,653
Long-term debt, excluding current portion	19,437		44,572
Total liabilities	74,707		90,574
Accumulated deficit	(12,644)		(4,417)
Common stock, additional paid-in capital, and accumulated other comprehensive loss	114,912		110,082
Total stockholders’ equity	102,268		105,665
Total liabilities and stockholders’ equity	176,975		$ 196,239
Adjustments | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash, cash equivalent and marketable securities		0
Accounts receivable, net		0
Inventories		0
Contract assets		3,205
Prepaid expenses and other current assets		0
Long-lived assets		0
Other non-current assets		0
Contract assets, long-term		5,963
Non-current deferred income tax asset		202
Total assets	10,677	9,370
Accounts payable, accrued expenses, and other current liabilities		0
Deferred revenue, current		(6,919)
Contract liabilities		11,039
Long-term contract liabilities		7,998
Other long-term liabilities		0
Long-term debt, excluding current portion		0
Total liabilities	$ 13,430	12,118
Accumulated deficit		(2,748)
Common stock, additional paid-in capital, and accumulated other comprehensive loss		0
Total stockholders’ equity		(2,748)
Total liabilities and stockholders’ equity		$ 9,370