Significant Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Significant Accounting Policies [Line Items]
Impairment losses on short-term investments									$ 0
Allowance for doubtful accounts receivable	$ 0								0
Inventory write-offs									774,000	$ 0	$ 0
Impairment of long-lived assets									0
Recognized net revenue on an accrual basis									8,458,000
Excise taxes									105,000	1,457,000	1,010,000
Other indirect taxes									867,000	818,000	266,000
Cost related to charitable care									1,675,000	1,376,000	836,000
Shipping and handling costs									3,389,000	1,385,000	553,000
Dividends declared									0
Dividends paid									0
Net revenues	$ 30,242,000	$ 21,674,000	$ 17,919,000	$ 13,053,000	$ 12,383,000	$ 8,953,000	$ 6,543,000	$ 5,208,000	82,888,000	33,087,000	15,490,000
Pension expense									529,000	404,000	205,000
Severance costs									430,000	356,000	307,000
Sales Revenue Net | Customer One | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Net revenues									$ 10,393,000	$ 5,595,000	$ 2,372,000
Concentration risk percentage									13.00%	17.00%	15.00%
Sales Revenue Net | Customer Two | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Net revenues									$ 7,010,000	$ 2,512,000	$ 2,014,000
Concentration risk percentage									9.00%	8.00%	12.00%
Employee Stock Option
Significant Accounting Policies [Line Items]
Share-based award requisite service period									4 years
Expected dividend yield									0.00%
Field Equipment Under Operating Leases
Significant Accounting Policies [Line Items]
Equipment write-downs included in cost of revenue									$ 6,436,000	$ 36,000	$ 12,000
Field Equipment Under Operating Leases | Minimum
Significant Accounting Policies [Line Items]
Property and equipment useful life									18 months
Field Equipment Under Operating Leases | Maximum
Significant Accounting Policies [Line Items]
Property and equipment useful life									36 months